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Coroutine

ref pep of `Coroutines with async and await syntax`, Future-like object is just an alias of Awaitable

V = 1
async def f():
    return V

c: Coroutine[None, None, int] = f()

try: c.send(None)
except StopIteraion as s: assert V == s.value

try: c.send(None)
except RuntimeError as e: assert str(e) == "cannot reuse already awaited coroutine"

# Also: V == await f()

pep for Asynchronous Generators

AsyncGenerator

V = 1
async def f(): yield V
ag = f()

ag_asend_obj = ag.asend(None)  #  or `anext(ag)`
try: ag_asend_obj.send(None)
except StopIteration as s: assert V == s.value


ag_asend_obj = ag.asend(None)  #  or `anext(ag, defval)` if wanting
# the next `send` raises `StopIteration` and its value to be `defval`

try: ag_asend_obj.send(None)
except StopAsyncIteration: pass   # iteration end

for ag_asend_obj, ref link of PyAsyncGenASend:

PyAsyncGenASend is a coroutine-like object...

PyAsyncGenAThrow is very similar to PyAsyncGenASend. The only difference is that PyAsyncGenAThrow.send(), when called first time, throws an exception into the parent agen object (instead of pushing a value into it.)