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- Bugfix: When a close frame with status NO_STATUS_RCVD is sent, send
and empty payload.
- Bugfix: Changing both encoding and decoding of the Host, from ascii
to idna.
- Bugfix: Support multiple Sec-WebSocket-Extensions and
Sec-WebSocket-Protocol headers.
- Accept bytes alongside string as path argument in
initiate_upgrade_connection.
- Check the state when sending events, raising if the event cannot be
sent in the current state.