Refactors SerializationDebugRequestHandler and DebugBackendConnector to improve performance.
Using a single SessionSerializer instance prevents creation of multiple (never stopped) executor services, serialization timeouts due to locks of VaadinSession because of concurrent requests, and excessive memory usage to store serialized data in memory for concurrent requests. Requests occurring during a serialization process are now silently ignored, (how it happens in production) since SessionSerializer has its own mechanism to guarantee that all changes are serialized.
Refactors SerializationDebugRequestHandler and DebugBackendConnector to improve performance. Using a single SessionSerializer instance prevents creation of multiple (never stopped) executor services, serialization timeouts due to locks of VaadinSession because of concurrent requests, and excessive memory usage to store serialized data in memory for concurrent requests. Requests occurring during a serialization process are now silently ignored, (how it happens in production) since SessionSerializer has its own mechanism to guarantee that all changes are serialized.
Part of #128 Fixes #125