Reducing Impact of random generation on span creation.

[hdost]

          > > > So i did a few tests looks like 2-7%. I'll post the full results when I'm back at my computer.

For the entropy, i like the idea, but the one question I have is will this sharing of the first 64 bits result in a skew in of sampling.

@shaun-cox any thoughts on this ?

I don't readily see any issues with sampling skew, but I'm not an expert. 64-bits of randomness in the trace id would seem to provide enough to make uniform sampling decisions.

I'll also reference this sdk issue which I came across while researching: open-telemetry/opentelemetry-specification#1413

open-telemetry/opentelemetry-specification#3411 Related.

Originally posted by @cijothomas in #1106 (comment)