Improve message filtering

To filter logs currently it is necessary to parse the messages that it passed to `ROARR.write` in JSON format, resulting in a potentially CPU-intensive filtering logic.

My proposal is to pass unserialized message as second parameter to `ROARR.write` to avoid JSON parsing for each log message.

Context: https://github.com/gajus/slonik/issues/277

Start at the ROARR.write implementation and trace how log messages are serialized and filtered. Define the behavior of the proposed second, unserialized message parameter, then verify that filtering can use it without parsing every JSON message and add tests for the new API behavior.

Written by the indexing model from the issue text.