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    use core::fmt;
    use core::marker::PhantomData;

    use {Poll, Future, Stream, Sink, StartSend};

    mod atomic_task;
    pub use self::atomic_task::AtomicTask;

    mod core;

    #[cfg(feature = "use_std")]
    mod std;
    #[cfg(feature = "use_std")]
    pub use self::std::*;
    #[cfg(not(feature = "use_std"))]
    pub use self::core::*;

    pub struct BorrowedTask<'a> {
        id: usize,
        unpark: BorrowedUnpark<'a>,
        events: BorrowedEvents<'a>,
        // Task-local storage
        map: &'a LocalMap,
    }

    fn fresh_task_id() -> usize {
        use core::sync::atomic::{AtomicUsize, Ordering, ATOMIC_USIZE_INIT};

        // TODO: this assert is a real bummer, need to figure out how to reuse
        //       old IDs that are no longer in use.
        //
        // Note, though, that it is intended that these ids go away entirely
        // eventually, see the comment on `is_current` below.
        static NEXT_ID: AtomicUsize = ATOMIC_USIZE_INIT;
        let id = NEXT_ID.fetch_add(1, Ordering::Relaxed);
        assert!(id < usize::max_value() / 2,
                "too many previous tasks have been allocated");
        id
    }

    fn with<F: FnOnce(&BorrowedTask) -> R, R>(f: F) -> R {
        unsafe {
            let task = get_ptr().expect("no Task is currently running");
            assert!(!task.is_null(), "no Task is currently running");
            f(&*(task as *const BorrowedTask))
        }
    }

    /// A handle to a "task", which represents a single lightweight "thread" of
    /// execution driving a future to completion.
    ///
    /// In general, futures are composed into large units of work, which are then
    /// spawned as tasks onto an *executor*. The executor is responsible for polling
    /// the future as notifications arrive, until the future terminates.
    ///
    /// This is obtained by the `task::current` function.
    #[derive(Clone)]
    pub struct Task {
        id: usize,
        unpark: TaskUnpark,
        events: UnparkEvents,
    }

    trait AssertSend: Send {}
    impl AssertSend for Task {}

    /// Returns a handle to the current task to call `notify` at a later date.
    ///
    /// The returned handle implements the `Send` and `'static` bounds and may also
    /// be cheaply cloned. This is useful for squirreling away the handle into a
    /// location which is then later signaled that a future can make progress.
    ///
    /// Implementations of the `Future` trait typically use this function if they
    /// would otherwise perform a blocking operation. When something isn't ready
    /// yet, this `current` function is called to acquire a handle to the current
    /// task, and then the future arranges it such that when the blocking operation
    /// otherwise finishes (perhaps in the background) it will `notify` the
    /// returned handle.
    ///
    /// It's sometimes necessary to pass extra information to the task when
    /// unparking it, so that the task knows something about *why* it was woken.
    /// See the `FutureQueue` documentation for details on how to do this.
    ///
    /// # Panics
    ///
    /// This function will panic if a task is not currently being executed. That
    /// is, this method can be dangerous to call outside of an implementation of
    /// `poll`.
    pub fn current() -> Task {
        with(|borrowed| {
            let unpark = borrowed.unpark.to_owned();
            let events = borrowed.events.to_owned();

            Task {
                id: borrowed.id,
                unpark: unpark,
                events: events,
            }
        })
    }

    #[doc(hidden)]
    #[deprecated(note = "renamed to `current`")]
    pub fn park() -> Task {
        current()
    }

    impl Task {
        /// Indicate that the task should attempt to poll its future in a timely
        /// fashion.
        ///
        /// It's typically guaranteed that, after calling `notify`, `poll` will
        /// be called at least once subsequently (unless the future has terminated).
        /// If the task is currently polling its future when `notify` is called, it
        /// must poll the future *again* afterwards, ensuring that all relevant
        /// events are eventually observed by the future.
        pub fn notify(&self) {
            self.events.notify();
            self.unpark.notify();
        }

        #[doc(hidden)]
        #[deprecated(note = "renamed to `notify`")]
        pub fn unpark(&self) {
            self.notify()
        }

        /// Returns `true` when called from within the context of the task.
        ///
        /// In other words, the task is currently running on the thread calling the
        /// function. Note that this is currently, and has historically, been
        /// implemented by tracking an `id` on every instance of `Spawn` created.
        /// When a `Spawn` is being polled it stores in thread-local-storage the id
        /// of the instance, and then `task::current` will return a `Task` that also
        /// stores this id.
        ///
        /// The intention of this function was to answer questions like "if I
        /// `notify` this task, is it equivalent to `task::current().notify()`?"
        /// The answer "yes" may be able to avoid some extra work to block the
        /// current task, such as sending a task along a channel or updating a
        /// stored `Task` somewhere. An answer of "no" typically results in doing
        /// the work anyway.
        ///
        /// Unfortunately this function has been somewhat buggy in the past and is
        /// not intended to be supported in the future. By simply matching `id` the
        /// intended question above isn't accurately taking into account, for
        /// example, unpark events (now deprecated, but still a feature). Thus many
        /// old users of this API weren't fully accounting for the question it was
        /// intended they were asking.
        ///
        /// This API continues to be implemented but will in the future, e.g. in the
        /// 0.1.x series of this crate, eventually return `false` unconditionally.
        /// It is intended that this function will be removed in the next breaking
        /// change of this crate. If you'd like to continue to be able to answer the
        /// example question above, it's recommended you use the
        /// `will_notify_current` method.
        ///
        /// If you've got questions about this though please let us know! We'd like
        /// to learn about other use cases here that we did not consider.
        ///
        /// # Panics
        ///
        /// This function will panic if no current future is being polled.
        #[deprecated(note = "intended to be removed, see docs for details")]
        pub fn is_current(&self) -> bool {
            with(|current| current.id == self.id)
        }

        /// This function is intended as a performance optimization for structures
        /// which store a `Task` internally.
        ///
        /// The purpose of this function is to answer the question "if I `notify`
        /// this task is it equivalent to `task::current().notify()`". An answer
        /// "yes" may mean that you don't actually need to call `task::current()`
        /// and store it, but rather you can simply leave a stored task in place. An
        /// answer of "no" typically means that you need to call `task::current()`
        /// and store it somewhere.
        ///
        /// As this is purely a performance optimization a valid implementation for
        /// this function is to always return `false`. A best effort is done to
        /// return `true` where possible, but false negatives may happen. Note that
        /// this function will not return a false positive, however.
        ///
        /// # Panics
        ///
        /// This function will panic if no current future is being polled.
        #[allow(deprecated)]
        pub fn will_notify_current(&self) -> bool {
            with(|current| {
                self.unpark.will_notify(&current.unpark) &&
                    self.events.will_notify(&current.events)
            })
        }
    }

    impl fmt::Debug for Task {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            f.debug_struct("Task")
             .finish()
        }
    }

    /// Representation of a spawned future/stream.
    ///
    /// This object is returned by the `spawn` function in this module. This
    /// represents a "fused task and future", storing all necessary pieces of a task
    /// and owning the top-level future that's being driven as well.
    ///
    /// A `Spawn` can be poll'd for completion or execution of the current thread
    /// can be blocked indefinitely until a notification arrives. This can be used
    /// with either futures or streams, with different methods being available on
    /// `Spawn` depending which is used.
    pub struct Spawn<T: ?Sized> {
        id: usize,
        data: LocalMap,
        obj: T,
    }

    /// Spawns a future or stream, returning it and the new task responsible for
    /// running it to completion.
    ///
    /// This function is the termination endpoint for running futures. This method
    /// will conceptually allocate a new task to run the given object, which is
    /// normally either a `Future` or `Stream`.
    ///
    /// This function is similar to the `thread::spawn` function but does not
    /// attempt to run code in the background. The future will not make progress
    /// until the methods on `Spawn` are called in turn.
    pub fn spawn<T>(obj: T) -> Spawn<T> {
        Spawn {
            id: fresh_task_id(),
            obj: obj,
            data: local_map(),
        }
    }

    impl<T: ?Sized> Spawn<T> {
        /// Get a shared reference to the object the Spawn is wrapping.
        pub fn get_ref(&self) -> &T {
            &self.obj
        }

        /// Get a mutable reference to the object the Spawn is wrapping.
        pub fn get_mut(&mut self) -> &mut T {
            &mut self.obj
        }

        /// Consume the Spawn, returning its inner object
        pub fn into_inner(self) -> T where T: Sized {
            self.obj
        }

        /// Polls the internal future, scheduling notifications to be sent to the
        /// `notify` argument.
        ///
        /// This method will poll the internal future, testing if it's completed
        /// yet. The `notify` argument is used as a sink for notifications sent to
        /// this future. That is, while the future is being polled, any call to
        /// `task::current()` will return a handle that contains the `notify`
        /// specified.
        ///
        /// If this function returns `NotReady`, then the `notify` should have been
        /// scheduled to receive a notification when poll can be called again.
        /// Otherwise if `Ready` or `Err` is returned, the `Spawn` task can be
        /// safely destroyed.
        ///
        /// Note that `notify` itself is passed as a shared reference, and is itself
        /// not required to be a `NotifyHandle`. The `Clone` and `Into` trait bounds
        /// will be used to convert this `notify` to a `NotifyHandle` if necessary.
        /// This construction can avoid an unnecessary atomic reference count bump
        /// in some situations.
        ///
        /// ## Unsafety and `id`
        ///
        /// This function and all other `*_notify` functions on this type will treat
        /// the `id` specified very carefully, explicitly calling functions like the
        /// `notify` argument's `clone_id` and `drop_id` functions. It should be
        /// safe to encode a pointer itself into the `id` specified, such as an
        /// `Arc<N>` or a `Box<N>`. The `clone_id` and `drop_id` functions are then
        /// intended to be sufficient for the memory management related to that
        /// pointer.
        pub fn poll_future_notify<N>(&mut self,
                                     notify: &N,
                                     id: usize) -> Poll<T::Item, T::Error>
            where N: Clone + Into<NotifyHandle>,
                  T: Future,
        {
            let mk = || notify.clone().into();
            self.enter(BorrowedUnpark::new(&mk, id), |f| f.poll())
        }

        /// Like `poll_future_notify`, except polls the underlying stream.
        pub fn poll_stream_notify<N>(&mut self,
                                     notify: &N,
                                     id: usize)
                                     -> Poll<Option<T::Item>, T::Error>
            where N: Clone + Into<NotifyHandle>,
                  T: Stream,
        {
            let mk = || notify.clone().into();
            self.enter(BorrowedUnpark::new(&mk, id), |s| s.poll())
        }

        /// Invokes the underlying `start_send` method with this task in place.
        ///
        /// If the underlying operation returns `NotReady` then the `notify` value
        /// passed in will receive a notification when the operation is ready to be
        /// attempted again.
        pub fn start_send_notify<N>(&mut self,
                                    value: T::SinkItem,
                                    notify: &N,
                                    id: usize)
                                   -> StartSend<T::SinkItem, T::SinkError>
            where N: Clone + Into<NotifyHandle>,
                  T: Sink,
        {
            let mk = || notify.clone().into();
            self.enter(BorrowedUnpark::new(&mk, id), |s| s.start_send(value))
        }

        /// Invokes the underlying `poll_complete` method with this task in place.
        ///
        /// If the underlying operation returns `NotReady` then the `notify` value
        /// passed in will receive a notification when the operation is ready to be
        /// attempted again.
        pub fn poll_flush_notify<N>(&mut self,
                                    notify: &N,
                                    id: usize)
                                    -> Poll<(), T::SinkError>
            where N: Clone + Into<NotifyHandle>,
                  T: Sink,
        {
            let mk = || notify.clone().into();
            self.enter(BorrowedUnpark::new(&mk, id), |s| s.poll_complete())
        }

        /// Invokes the underlying `close` method with this task in place.
        ///
        /// If the underlying operation returns `NotReady` then the `notify` value
        /// passed in will receive a notification when the operation is ready to be
        /// attempted again.
        pub fn close_notify<N>(&mut self,
                               notify: &N,
                               id: usize)
                               -> Poll<(), T::SinkError>
            where N: Clone + Into<NotifyHandle>,
                  T: Sink,
        {
            let mk = || notify.clone().into();
            self.enter(BorrowedUnpark::new(&mk, id), |s| s.close())
        }

        fn enter<F, R>(&mut self, unpark: BorrowedUnpark, f: F) -> R
            where F: FnOnce(&mut T) -> R
        {
            let borrowed = BorrowedTask {
                id: self.id,
                unpark: unpark,
                events: BorrowedEvents::new(),
                map: &self.data,
            };
            let obj = &mut self.obj;
            set(&borrowed, || f(obj))
        }
    }

    impl<T: fmt::Debug + ?Sized> fmt::Debug for Spawn<T> {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            f.debug_struct("Spawn")
             .field("obj", &&self.obj)
             .finish()
        }
    }

    /// A trait which represents a sink of notifications that a future is ready to
    /// make progress.
    ///
    /// This trait is provided as an argument to the `Spawn::*_notify` family of
    /// functions. It's transitively used as part of the `Task::notify` method to
    /// internally deliver notifications of readiness of a future to move forward.
    ///
    /// An instance of `Notify` has one primary method, `notify`, which is given a
    /// contextual argument as to what's being notified. This contextual argument is
    /// *also* provided to the `Spawn::*_notify` family of functions and can be used
    /// to reuse an instance of `Notify` across many futures.
    ///
    /// Instances of `Notify` must be safe to share across threads, and the methods
    /// be invoked concurrently. They must also live for the `'static` lifetime,
    /// not containing any stack references.
    pub trait Notify: Send + Sync {
        /// Indicates that an associated future and/or task are ready to make
        /// progress.
        ///
        /// Typically this means that the receiver of the notification should
        /// arrange for the future to get poll'd in a prompt fashion.
        ///
        /// This method takes an `id` as an argument which was transitively passed
        /// in from the original call to `Spawn::*_notify`. This id can be used to
        /// disambiguate which precise future became ready for polling.
        ///
        /// # Panics
        ///
        /// Since `unpark` may be invoked from arbitrary contexts, it should
        /// endeavor not to panic and to do as little work as possible. However, it
        /// is not guaranteed not to panic, and callers should be wary. If a panic
        /// occurs, that panic may or may not be propagated to the end-user of the
        /// future that you'd otherwise wake up.
        fn notify(&self, id: usize);

        /// This function is called whenever a new copy of `id` is needed.
        ///
        /// This is called in one of two situations:
        ///
        /// * A `Task` is being created through `task::current` while a future is
        ///   being polled. In that case the instance of `Notify` passed in to one
        ///   of the `poll_*` functions is called with the `id` passed into the same
        ///   `poll_*` function.
        /// * A `Task` is itself being cloned. Each `Task` contains its own id and a
        ///   handle to the `Notify` behind it, and the task's `Notify` is used to
        ///   clone the internal `id` to assign to the new task.
        ///
        /// The `id` returned here will be stored in the `Task`-to-be and used later
        /// to pass to `notify` when the `Task::notify` function is called on that
        /// `Task`.
        ///
        /// Note that typically this is just the identity function, passing through
        /// the identifier. For more unsafe situations, however, if `id` is itself a
        /// pointer of some kind this can be used as a hook to "clone" the pointer,
        /// depending on what that means for the specified pointer.
        fn clone_id(&self, id: usize) -> usize {
            id
        }

        /// All instances of `Task` store an `id` that they're going to internally
        /// notify with, and this function is called when the `Task` is dropped.
        ///
        /// This function provides a hook for schemes which encode pointers in this
        /// `id` argument to deallocate resources associated with the pointer. It's
        /// guaranteed that after this function is called the `Task` containing this
        /// `id` will no longer use the `id`.
        fn drop_id(&self, id: usize) {
            drop(id);
        }
    }

    /// Sets the `NotifyHandle` of the current task for the duration of the provided
    /// closure.
    ///
    /// This function takes a type that can be converted into a notify handle,
    /// `notify` and `id`, and a closure `f`. The closure `f` will be executed such
    /// that calls to `task::current()` will store a reference to the notify handle
    /// provided, not the one previously in the environment.
    ///
    /// Note that calls to `task::current()` in the closure provided *will not* be
    /// equivalent to `task::current()` before this method is called. The two tasks
    /// returned will notify different handles, and the task handles pulled out
    /// during the duration of this closure will not notify the previous task. It's
    /// recommended that you call `task::current()` in some capacity before calling
    /// this function to ensure that calls to `task::current()` inside of this
    /// closure can transitively wake up the outer task.
    ///
    /// # Panics
    ///
    /// This function will panic if it is called outside the context of a future's
    /// task. This is only valid to call once you've already entered a future via
    /// `Spawn::poll_*` functions.
    pub fn with_notify<F, T, R>(notify: &T, id: usize, f: F) -> R
        where F: FnOnce() -> R,
              T: Clone + Into<NotifyHandle>,
    {
        with(|task| {
            let mk = || notify.clone().into();
            let new_task = BorrowedTask {
                id: task.id,
                unpark: BorrowedUnpark::new(&mk, id),
                events: task.events,
                map: task.map,
            };

            set(&new_task, f)
        })
    }

    /// An unsafe trait for implementing custom forms of memory management behind a
    /// `Task`.
    ///
    /// The `futures` critically relies on "notification handles" to extract for
    /// futures to contain and then later inform that they're ready to make
    /// progress. These handles, however, must be cheap to create and cheap
    /// to clone to ensure that this operation is efficient throughout the
    /// execution of a program.
    ///
    /// Typically this sort of memory management is done in the standard library
    /// with the `Arc` type. An `Arc` is relatively cheap to allocate an is
    /// quite cheap to clone and pass around. Plus, it's 100% safe!
    ///
    /// When working outside the standard library, however, you don't always have
    /// and `Arc` type available to you. This trait, `UnsafeNotify`, is intended
    /// to be the "unsafe version" of the `Notify` trait. This trait encodes the
    /// memory management operations of a `Task`'s notification handle, allowing
    /// custom implementations for the memory management of a notification handle.
    ///
    /// Put another way, the core notification type in this library,
    /// `NotifyHandle`, simply internally contains an instance of
    /// `*mut UnsafeNotify`. This "unsafe trait object" is then used exclusively
    /// to operate with, dynamically dispatching calls to clone, drop, and notify.
    /// Critically though as a raw pointer it doesn't require a particular form
    /// of memory management, allowing external implementations.
    ///
    /// A default implementation of the `UnsafeNotify` trait is provided for the
    /// `Arc` type in the standard library. If the `use_std` feature of this crate
    /// is not available however, you'll be required to implement your own
    /// instance of this trait to pass it into `NotifyHandle::new`.
    ///
    /// # Unsafety
    ///
    /// This trait is manually encoding the memory management of the underlying
    /// handle, and as a result is quite unsafe to implement! Implementors of
    /// this trait must guarantee:
    ///
    /// * Calls to `clone_raw` produce uniquely owned handles. It should be safe
    ///   to drop the current handle and have the returned handle still be valid.
    /// * Calls to `drop_raw` work with `self` as a raw pointer, deallocating
    ///   resources associated with it. This is a pretty unsafe operation as it's
    ///   invalidating the `self` pointer, so extreme care needs to be taken.
    ///
    /// In general it's recommended to review the trait documentation as well as
    /// the implementation for `Arc` in this crate. When in doubt ping the
    /// `futures` authors to clarify an unsafety question here.
    pub unsafe trait UnsafeNotify: Notify {
        /// Creates a new `NotifyHandle` from this instance of `UnsafeNotify`.
        ///
        /// This function will create a new uniquely owned handle that under the
        /// hood references the same notification instance. In other words calls
        /// to `notify` on the returned handle should be equivalent to calls to
        /// `notify` on this handle.
        ///
        /// # Unsafety
        ///
        /// This trait is unsafe to implement, as are all these methods. This
        /// method is also unsafe to call as it's asserting the `UnsafeNotify`
        /// value is in a consistent state. In general it's recommended to
        /// review the trait documentation as well as the implementation for `Arc`
        /// in this crate. When in doubt ping the `futures` authors to clarify
        /// an unsafety question here.
        unsafe fn clone_raw(&self) -> NotifyHandle;

        /// Drops this instance of `UnsafeNotify`, deallocating resources
        /// associated with it.
        ///
        /// This method is intended to have a signature such as:
        ///
        /// ```ignore
        /// fn drop_raw(self: *mut Self);
        /// ```
        ///
        /// Unfortunately in Rust today that signature is not object safe.
        /// Nevertheless it's recommended to implement this function *as if* that
        /// were its signature. As such it is not safe to call on an invalid
        /// pointer, nor is the validity of the pointer guaranteed after this
        /// function returns.
        ///
        /// # Unsafety
        ///
        /// This trait is unsafe to implement, as are all these methods. This
        /// method is also unsafe to call as it's asserting the `UnsafeNotify`
        /// value is in a consistent state. In general it's recommended to
        /// review the trait documentation as well as the implementation for `Arc`
        /// in this crate. When in doubt ping the `futures` authors to clarify
        /// an unsafety question here.
        unsafe fn drop_raw(&self);
    }

    /// A `NotifyHandle` is the core value through which notifications are routed
    /// in the `futures` crate.
    ///
    /// All instances of `Task` will contain a `NotifyHandle` handle internally.
    /// This handle itself contains a trait object pointing to an instance of the
    /// `Notify` trait, allowing notifications to get routed through it.
    ///
    /// The `NotifyHandle` type internally does not codify any particular memory
    /// management strategy. Internally it contains an instance of `*mut
    /// UnsafeNotify`, and more details about that trait can be found on its own
    /// documentation. Consequently, though, the one constructor of this type,
    /// `NotifyHandle::new`, is `unsafe` to call. It is not recommended to call
    /// this constructor directly.
    ///
    /// If you're working with the standard library then it's recommended to
    /// work with the `Arc` type. If you have a struct, `T`, which implements the
    /// `Notify` trait, then you can construct this with
    /// `NotifyHandle::from(t: Arc<T>)`. The coercion to `UnsafeNotify` will
    /// happen automatically and safely for you.
    ///
    /// When working externally from the standard library it's recommended to
    /// provide a similar safe constructor for your custom type as opposed to
    /// recommending an invocation of `NotifyHandle::new` directly.
    pub struct NotifyHandle {
        inner: *mut UnsafeNotify,
    }

    unsafe impl Send for NotifyHandle {}
    unsafe impl Sync for NotifyHandle {}

    impl NotifyHandle {
        /// Constructs a new `NotifyHandle` directly.
        ///
        /// Note that most code will not need to call this. Implementers of the
        /// `UnsafeNotify` trait will typically provide a wrapper that calls this
        /// but you otherwise shouldn't call it directly.
        ///
        /// If you're working with the standard library then it's recommended to
        /// use the `NotifyHandle::from` function instead which works with the safe
        /// `Arc` type and the safe `Notify` trait.
        #[inline]
        pub unsafe fn new(inner: *mut UnsafeNotify) -> NotifyHandle {
            NotifyHandle { inner: inner }
        }

        /// Invokes the underlying instance of `Notify` with the provided `id`.
        pub fn notify(&self, id: usize) {
            unsafe { (*self.inner).notify(id) }
        }

        fn clone_id(&self, id: usize) -> usize {
            unsafe { (*self.inner).clone_id(id) }
        }

        fn drop_id(&self, id: usize) {
            unsafe { (*self.inner).drop_id(id) }
        }
    }

    impl Clone for NotifyHandle {
        #[inline]
        fn clone(&self) -> Self {
            unsafe {
                (*self.inner).clone_raw()
            }
        }
    }

    impl fmt::Debug for NotifyHandle {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            f.debug_struct("NotifyHandle")
             .finish()
        }
    }

    impl Drop for NotifyHandle {
        fn drop(&mut self) {
            unsafe {
                (*self.inner).drop_raw()
            }
        }
    }

    /// Marker for a `T` that is behind &'static.
    struct StaticRef<T>(PhantomData<T>);

    impl<T: Notify> Notify for StaticRef<T> {
        fn notify(&self, id: usize) {
            let me = unsafe { &*(self as *const _ as *const T) };
            me.notify(id);
        }

        fn clone_id(&self, id: usize) -> usize {
            let me = unsafe { &*(self as *const _ as *const T) };
            me.clone_id(id)
        }

        fn drop_id(&self, id: usize) {
            let me = unsafe { &*(self as *const _ as *const T) };
            me.drop_id(id);
        }
    }

    unsafe impl<T: Notify + 'static> UnsafeNotify for StaticRef<T> {
        unsafe fn clone_raw(&self) -> NotifyHandle {
            NotifyHandle::new(self as *const _ as *mut StaticRef<T>)
        }

        unsafe fn drop_raw(&self) {}
    }

    impl<T: Notify> From<&'static T> for NotifyHandle {
        fn from(src : &'static T) -> NotifyHandle {
            unsafe { NotifyHandle::new(src as *const _ as *mut StaticRef<T>) }
        }
    }

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