Function hyper_executor_poll 

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

Available on crate feature ffi and hyper_unstable_ffi only.

Polls the executor, trying to make progress on any tasks that can do so.

If any task from the executor is ready, returns one of them. The way tasks signal being finished is internal to Hyper. The order in which tasks are returned is not guaranteed. Use userdata to distinguish between tasks.

To avoid a memory leak, the task must eventually be consumed by hyper_task_free.

If there are no ready tasks, this returns NULL.