ARM build sometimes times out when testing with race conditions.

[Excaleo]

Context

Sometimes the ARM build times out when running the tests with the race detector. This is hard to reproduce since it only happens sometimes in travis CI

Potential causes

From this build result, it seems this is a degradation within the ARM compiled binary. https://app.travis-ci.com/github/atlassian/gostatsd/jobs/533596613#L843 in the receive function.

BenchmarkReceive-80 1 1228779055 ns/op 262749480 B/op 12341 allocs/op

For comparison, this is the same benchmark in the AMD64 build.

BenchmarkReceive-2 105783 11717 ns/op 18962 B/op 4 allocs/op

Attempted Fixes

In #383, the timeout was raised from 1 second to 1.4 seconds for that specific test case, this did not fix the issue.

[tiedotguy]

I believe the -80 in BenchmarkReceive-80 is the number of cores, but I suspect it's really only got 2, so we're probably thrashing it.