Why must metric values be ints||floats? #668

Hello,

I've searched in various places and looked at the commit logs and can't find any satisfactory answer to this question: why does Diamond constrain Metric.value to an int||float? What's the reason behind this? Is it simply due to historical reasons, i.e. Diamond was originally developed alongside Graphite? Is it possible to extend the allowed types to include 'string' as well? (I do understand that string type isn't suitable for apps backed by time-series databases).

Thanks,
David