Set up a benchmark for our trampolines.

[non]

This commit adds a new benchmark to the bench project.
It updates the version of JMH that we are using, and
also adds a new, hidden Eval subtype which improves
the performance of Eval.defer.

[non]

Here's the benchmark result running on my machine:

Benchmark                    Mode  Cnt      Score      Error  Units
TrampolineBench.eval        thrpt    3  23049.351 ± 3891.576  ops/s
TrampolineBench.stdlib      thrpt    3  11827.608 ± 1919.654  ops/s
TrampolineBench.trampoline  thrpt    3   5743.017 ±  197.309  ops/s

(Run with bench/jmh:run -i 3 -wi 3 -f1 -t1 cats.bench.TrampolineBench)

[ceedubs]

Are the build failures random or related to this?

[non]

I'm looking into it. It doesn't seem like Travis flakiness.

[non]

So validate seems to reliably pass locally. It could be an issue of memory/resources available.

[ceedubs]

I restarted the builds and this time they worked in 2.10 but not 2.11. It does seem like a quirky sporadic/resource issue, but if we aren't seeing this outside of this branch, I'm also a little hesitant to merge this PR simply because I don't want us to start completely ignoring build statuses. @inthenow do you have any ideas?

[non]

Maybe we should set up Contained-Based builds? I wonder if that would help: http://blog.travis-ci.com/2014-12-17-faster-builds-with-container-based-infrastructure/

EDIT: This article looks old -- maybe we are already doing this. I need to investigate further.

[codecov-io]

Current coverage is 65.16%

Merging #519 into master will increase coverage by +0.07% as of b4a9df2

@@            master    #519   diff @@
======================================
  Files          156     156       
  Stmts         2418    2420     +2
  Branches        68      68       
  Methods          0       0       
======================================
+ Hit           1574    1577     +3
  Partial          0       0       
+ Missed         844     843     -1

Review entire Coverage Diff as of b4a9df2

Powered by Codecov. Updated on successful CI builds.

[codecov-io]

Current coverage is 65.16%

Merging #519 into master will increase coverage by +0.07% as of f537fec

@@            master    #519   diff @@
======================================
  Files          156     156       
  Stmts         2418    2420     +2
  Branches        68      68       
  Methods          0       0       
======================================
+ Hit           1574    1577     +3
  Partial          0       0       
+ Missed         844     843     -1

Review entire Coverage Diff as of f537fec

Powered by Codecov. Updated on successful CI builds.

[non]

Awesome. We seem to have overcome the previous build flakiness!

[ceedubs]

👍

[adelbertc]

👍