Cheatsheet for Futures

// Constructing leaf futures fn empty () -> Future<T, E> fn ok (T) -> Future<T, E> fn err (E) -> Future<T, E> fn result(Result<T, E>) -> Future<T, E> // General future constructor fn poll_fn(FnMut(thread_local!(Task)) -> Poll<T, E>) -> Future<T, E> // Mapping futures fn Future::map (Future<T, E>, FnOnce(T) -> U) -> Future<U, E> fn Future::map_err (Future<T, E>, FnOnce(E) -> F) -> Future<T, F> fn F