Function hyper::ffi::hyper_executor_poll

#[no_mangle]
pub extern "C" fn hyper_executor_poll(
    exec: *const hyper_executor
) -> *mut hyper_task

This is supported on crate feature ffi only.

Polls the executor, trying to make progress on any tasks that have notified that they are ready again.

If ready, returns a task from the executor that has completed.

If there are no ready tasks, this returns NULL.