class Protocol::HTTP2::Frame

def header
	unless VALID_LENGTH.include? @length
		raise ProtocolError, "Invalid frame length: #{@length.inspect}"
	end
	
	unless VALID_STREAM_ID.include? @stream_id
		raise ProtocolError, "Invalid stream identifier: #{@stream_id.inspect}"
	end
	
	[
		# These are guaranteed correct due to the length check above.
		@length >> LENGTH_HISHIFT,
		@length & LENGTH_LOMASK,
		@type,
		@flags,
		@stream_id
	].pack(HEADER_FORMAT)
end