Struct TaskCallbacks 

pub struct TaskCallbacks {
    pub before: fn() -> Option<*const ()>,
    pub enter: fn(*const ()) -> *const (),
    pub exit: fn(*const ()),
    pub after: fn(*const ()),
}

Callbacks for instrumenting spawned tasks.

Configure a factory returning them with Builder::task_callbacks or the task_callbacks argument of #[ntex::main] and #[ntex::test]. The factory is called once on every thread of the system, when the thread joins it. They apply when crate::spawn, crate::spawn_detached, spawn_sendable, crate::rt::spawn, or crate::rt::spawn_detached wraps a future on a thread of the configured system, including its arbiters. They do not apply retroactively, to direct crate::rt::Runtime spawning methods, or on threads without a system.

• before runs synchronously when the future is wrapped. Returning None disables the remaining callbacks for that future.
• enter receives the task’s pointer before each poll and returns a pointer representing the previous context.
• exit receives that previous-context pointer after the poll, including when polling unwinds.
• after receives the task’s original pointer when its callback state is dropped, including cancellation before the first poll.

Pointers are opaque to the runtime, which never dereferences them. Keep the state returned by before valid until after, and the state returned by enter valid until its matching exit. Callbacks of a thread run only on that thread and may be called while other tasks are spawned.

Fields

before: fn() -> Option<*const ()>

Called when a future is wrapped, returns the task’s pointer.

enter: fn(*const ()) -> *const ()

Called before each poll, returns the previous context.

exit: fn(*const ())

Called after each poll with the value returned by enter.

after: fn(*const ())

Called once with the task’s pointer when its callback state is dropped.

Trait Implementations

impl Clone for TaskCallbacks

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for TaskCallbacks

impl Debug for TaskCallbacks

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.