When using bigquerystorage stream writer api, each write requests creates a new WriterStream object.
A successful write operation ends with an RuntimeException which is handled by the StreamWorker.
Stream worker is printing the "successful error" log messages at an INFO level. Additionally, during product development more log messages in the Stream Worker were moved from FINE level into INFO level: PR 1999 and PR 2017.
As a result of this, every successful write stream now prints quite a lot of what I consider to be non-info level stuff cluttering the logs.
If the maintainers agree that this could be improved, I am willing to contribute updating the log levels as this looks to be a "good first issue" type of problem.