Refactor concurrency setup

Rather than slice the id slice into chunks
for the N go-routines desired, which will
all be sharing the same underlaying array, which
I suspect was actually causing issues - just feed out
numbers on a channel to any number or routines, which is
thread safe.

This seems to have much better performance than all the
array access
Increase buffer to make sure not bottleneck

Just making sure that the networking stuff is not getting blocked
waiting for an io operation