The 'close'
event is emitted when the Http2Stream
is destroyed. Once
this event is emitted, the Http2Stream
instance is no longer usable.
The HTTP/2 error code used when closing the stream can be retrieved using
the http2stream.rstCode
property. If the code is any value other than
NGHTTP2_NO_ERROR
(0
), an 'error'
event will have also been emitted.