Parse message remove regexp

Remove the use of regexp to parse incoming message lines, using bytes functions instead.

```
benchmark                   old ns/op     new ns/op     delta
BenchmarkParseMessage-8     2642          1256          -52.46%

benchmark                   old allocs     new allocs     delta
BenchmarkParseMessage-8     7              6              -14.29%

benchmark                   old bytes     new bytes     delta
BenchmarkParseMessage-8     397           179           -54.91%
```