make Huffman methods class methods to avoid unnecessary allocations

[froydnj]

Protocol::HPACK::Huffman doesn't maintain any state, so there's no reason for encode/decode to be instance methods. Making them class methods means we can avoid allocating instances during header encoding/decoding, which improves performance (~2% on my machine, but the benchmark is a bit noisy).

Types of Changes

• Performance improvement.

Contribution

• I added tests for my changes.
• I tested my changes locally.
• I agree to the Developer's Certificate of Origin 1.1.

[ioquatix]

Thanks for this nice improvement.

[ioquatix]

Some rough comparisons:

HEAD

________________________________________________________
Executed in   18.68 secs    fish           external
   usr time   17.59 secs  326.00 micros   17.59 secs
   sys time    1.03 secs  146.00 micros    1.03 secs

Before your changes

________________________________________________________
Executed in   21.79 secs    fish           external
   usr time   20.63 secs  323.00 micros   20.63 secs
   sys time    1.11 secs  145.00 micros    1.11 secs

[froydnj]

Some rough comparisons:

HEAD

________________________________________________________
Executed in   18.68 secs    fish           external
   usr time   17.59 secs  326.00 micros   17.59 secs
   sys time    1.03 secs  146.00 micros    1.03 secs

Before your changes

________________________________________________________
Executed in   21.79 secs    fish           external
   usr time   20.63 secs  323.00 micros   20.63 secs
   sys time    1.11 secs  145.00 micros    1.11 secs

Cool! I've pushed #12 and I have a slightly more complex change for improving header encoding/decoding that'll have to wait until tomorrow.

[froydnj]

And thank you for merging all of these so quickly!