benchmark

getmapkeys

benchmark append with init [] and append without init []

BenchmarkWithInit-4             100000          16551 ns/op
BenchmarkWithoutInit-4          50000           25053 ns/op

goroutine

benchmark go func and chan <- work

BenchmarkGoRoutine              300000          8475 ns/op
BenchmarkGoChan                 1000000         2678 ns/op

distinct

benchmark by map and by slice

BenchmarkByMap-4                20000           72772 ns/op
BenchmarkBySlice-4              5000            263969 ns/op