What is best design pattern to avoid cross dependency

Can some one suggest the best design pattern for bellow scenario,

Assume that i am going to run a performance test for message handling via a client, There i have 3 classes incorporated, Client - send and receive message. Stat_calculator - measure the latency for message Test_Manager - Manage test cycles an publish results

Above 3 classes have inter-dependencies between each others. I suppose to use "Mediator" pattern. Is that the best pattern for this ?