Compression summary is global across all clients.

Compression summary, namely compressedAccumulation and uncompressedAccumulation in CellHandler are accumulated globally. This was OK for local testing, but if two or more clients connect to the same CellHandler then the summary info is flawed.

We need to save these two accumulations in some HashMap, where key is the client identification. We will probably use baseRequest.getRemoteInetSocketAddress().

The next step will be to clean statistics from inactive clients.