Type hint all ctx managers in _ringbuf.py
Remove unnecesary send lock on ring chan sender
Handle EOF on ring chan receiver
Rename ringbuf tests to make it less redundant
Add EOF signaling mechanism
Support proper `receive_some` end of stream semantics
Add StapledStream non-ipc test
Create MsgpackRBStream similar to MsgpackTCPStream for buffered whole-msg reads
Add EventFD.read cancellation on EventFD.close mechanism using cancel scope
Add test for eventfd cancellation
Improve and add docstrings
Add trio.StrictFIFOLock on sender.send_all
Support max_bytes argument on receive_some, keep track of write_ptr on receiver
Add max_bytes receive test test_ringbuf_max_bytes
Add docstrings to all ringbuf tests
Remove EFD_NONBLOCK support, not necesary anymore since we can use abandon_on_cancel=True on trio.to_thread.run_sync
Close eventfd's after usage on open_ringbuf
Guillermo Rodriguez