Configurable compression algorithms

[ppkarwasz]

[Also posted to this log4j-user@logging thread]

Commons Compress offers a lot of algorithm specific parameters like GzipParameters.

While revamping the compression subsystem of the rolling appender in PR #2921, we were wondering if the Log4j community needs to tweak these parameters or is satisfied with using the default values.
If this is the case, we are open to contributions that make compression more configurable.

Such a feature would probably require changes not only to Log4j, but also to Commons Compress, to make those parameters more easily accessible to Log4j developers.
If you find this feature interesting, can you explain your use case?

Our working assumption is that this kind of tweak is not generally useful and we are thinking about deprecating the compressionLevel configuration attribute of rollover strategies and removing it in 3.x.