Re-organize directory structure (#4971)

See discussion in #2491

Co-authored-by: Ivan Levkivskyi <ilevkivskyi@dropbox.com>

stdlib/asyncio/futures.pyi

@@ -0,0 +1,65 @@
+import sys
+from concurrent.futures._base import Error, Future as _ConcurrentFuture
+from typing import Any, Awaitable, Callable, Generator, Iterable, List, Optional, Tuple, TypeVar, Union
+
+from .events import AbstractEventLoop
+
+if sys.version_info < (3, 8):
+    from concurrent.futures import CancelledError as CancelledError, TimeoutError as TimeoutError
+    class InvalidStateError(Error): ...
+
+if sys.version_info >= (3, 7):
+    from contextvars import Context
+
+if sys.version_info >= (3, 9):
+    from types import GenericAlias
+
+_T = TypeVar("_T")
+_S = TypeVar("_S")
+
+if sys.version_info < (3, 7):
+    class _TracebackLogger:
+        exc: BaseException
+        tb: List[str]
+        def __init__(self, exc: Any, loop: AbstractEventLoop) -> None: ...
+        def activate(self) -> None: ...
+        def clear(self) -> None: ...
+        def __del__(self) -> None: ...
+
+def isfuture(obj: object) -> bool: ...
+
+class Future(Awaitable[_T], Iterable[_T]):
+    _state: str
+    _exception: BaseException
+    _blocking = False
+    _log_traceback = False
+    def __init__(self, *, loop: Optional[AbstractEventLoop] = ...) -> None: ...
+    def __repr__(self) -> str: ...
+    def __del__(self) -> None: ...
+    if sys.version_info >= (3, 7):
+        def get_loop(self) -> AbstractEventLoop: ...
+        def _callbacks(self: _S) -> List[Tuple[Callable[[_S], Any], Context]]: ...
+        def add_done_callback(self: _S, __fn: Callable[[_S], Any], *, context: Optional[Context] = ...) -> None: ...
+    else:
+        @property
+        def _callbacks(self: _S) -> List[Callable[[_S], Any]]: ...
+        def add_done_callback(self: _S, __fn: Callable[[_S], Any]) -> None: ...
+    if sys.version_info >= (3, 9):
+        def cancel(self, msg: Optional[str] = ...) -> bool: ...
+    else:
+        def cancel(self) -> bool: ...
+    def cancelled(self) -> bool: ...
+    def done(self) -> bool: ...
+    def result(self) -> _T: ...
+    def exception(self) -> Optional[BaseException]: ...
+    def remove_done_callback(self: _S, __fn: Callable[[_S], Any]) -> int: ...
+    def set_result(self, __result: _T) -> None: ...
+    def set_exception(self, __exception: Union[type, BaseException]) -> None: ...
+    def __iter__(self) -> Generator[Any, None, _T]: ...
+    def __await__(self) -> Generator[Any, None, _T]: ...
+    @property
+    def _loop(self) -> AbstractEventLoop: ...
+    if sys.version_info >= (3, 9):
+        def __class_getitem__(cls, item: Any) -> GenericAlias: ...
+
+def wrap_future(future: Union[_ConcurrentFuture[_T], Future[_T]], *, loop: Optional[AbstractEventLoop] = ...) -> Future[_T]: ...