should allow logger to be replaced

[flowchartsman]

By having a hard-coded unexported logger in the parser, it is impossible to use for a service that doesn't want to log or wants to control how it logs. The user should be able to set their own logs or, ideally, the parser should allow them to process individual messages as they see fit.

[Xumeiquer]

Hi, that's true. It would be a good enhancement for YaGo. I will think about it. In any case you can also do a PR with the feature.