Use precompiled struct methods for pack, unpack data

[umax]

Notes for struct usage optimizations: https://docs.python.org/2/library/struct.html#classes
Regarding string formatting:

In [1]: %timeit '%s' % 1
14.7 ns ± 0.325 ns per loop (mean ± std. dev. of 7 runs, 100000000 loops each)

In [2]: %timeit '{0}'.format(1)
134 ns ± 2.93 ns per loop (mean ± std. dev. of 7 runs, 10000000 loops each)

[brian-brazil]

put an _ in front of these so they aren't exported

[umax]

ok

[brian-brazil]

Explain what you're doing a bit more. Not everyone will have seen the relevant talks by Raymond Hettinger

[umax]

https://wiki.python.org/moin/PythonSpeed/PerformanceTips

[brian-brazil]

I know why this works, but someone reading this code might not. A quick comment will help future readers of the code.

[umax]

fixed

[brian-brazil]

Thanks!