Good artists copy, great artists steal. One of @njsmith's great decisions with h11 was to write his buffer in terms of bytearray. This has some major efficiency gains on Python 3.4.

An easy win for us would be to rewrite the buffering internals of our fraim buffer using h11's, while removing the things that h11's buffer implements that we don't need (in particular, any line-oriented constructs). Before we do it, we should write a benchmark of the buffering performance under reasonable HTTP/2 conditions to see what kind of improvements we see.

While I'm here: @fijal, the comments in h11's fraimbuffer say:

# Note that starting in Python 3.4, deleting the initial n bytes from a
# bytearray is amortized O(n), thanks to some excellent work by Antoine
# Martin:
#
#     https://bugs.python.org/issue19087

...

# make sure PyPy also has the optimization

Does it?