class Protocol::HTTP::Header::Priority

@returns [Integer | Nil] the urgency level if specified, or `nil` if not present.

Returns the urgency level if specified. 0 is the highest priority, and 7 is the lowest.

def urgency(default = DEFAULT_URGENCY)
	if value = self.find { |value| value.start_with?("u=") }
		_, level = value.split("=", 2)
		return level.to_i
	end
	
	return default
end