fix slot lock, added debug info

receiver/src/data_cache.cpp

receiver/src/data_cache.h

receiver/src/receiver_error.h

receiver/src/request.cpp

receiver/src/request.h

...iver/src/request_handler/request_handler_receive_data.cpp

receiver/unittests/receiver_mocking.h

...sts/request_handler/test_request_handler_receive_data.cpp

receiver/unittests/test_datacache.cpp

receiver/unittests/test_request.cpp