Write the header for an application-specific extension of two data bytes

After writing the header, clients should write the two data bytes.

Property definitions

msgpack :: write $ Writer :: write_msgpack_fixext2
	# Write the header for an application-specific extension of two data bytes
	#
	# After writing the header, clients should write the two data bytes.
	fun write_msgpack_fixext2(typ: Int)
	do
		write_byte 0xD5
		write_byte typ
	end
lib/msgpack/write.nit:457,2--464,4