Parse a legacy HTTP+SSE event stream looking for the first endpoint event,
returning its data: payload (the message-POST URI) in uri. Returns false
if no endpoint event is found in the supplied buffer. Handles CRLF and LF
line endings and the optional single leading space after data:.
Parse a legacy HTTP+SSE event stream looking for the first endpoint event, returning its data: payload (the message-POST URI) in uri. Returns false if no endpoint event is found in the supplied buffer. Handles CRLF and LF line endings and the optional single leading space after data:.