package provides functions to help with concurrent generation of unique, incremental counters.
Uint64Counter.Get returns a uint64 counter value.
each call to the function will cause the counter to increment until it rolls
over to 0 at the unint64 max value.
BigIntCounter.Get returns a big int counter value.
each call to the function will cause the counter to increment.
This counter will never roll over, and increases infinitely