Listener receives packets from the udp buffer, parses them and feeds both the Metrics channel as well as the metricAmounts channel.

ParseLine turns a line into a *Metric (or not) and returns an error if the line was invalid.

ParseLine with lexer impl.

ParseMessage turns byte data into a slice of metric pointers note that it creates "invalid line" metrics itself, upon invalid lines, which will get passed on and aggregated along with the other metrics.