A HydraExpress client proxy is multithread-hot. A proxy may create threads as necessary to handle requests to the server. However, the proxy itself is not designed to accept simultaneous requests from multiple threads. A multithreaded application that shares a client proxy amongst threads must protect the proxy from simultaneous access.
If you are a SourcePro customer, we recommend using the classes provided by the Threads Module of SourcePro Core, to synchronize access to a proxy shared among threads.