The current C# driver side implementation of compression only works with OP_MESSAGE, which in turn was introduced in server 3.6.

However, compression itself was introduced in server 3.4.

The C# driver currently has issues when compression is configured and the server is version 3.4.

One issue is that we don't compress OP_QUERY messages sent to the server.

Another issue is that we don't always handle OP_COMPRESSED replies from the server correctly (in particular when raising CommandStartedEvent).