add integration test for memory buffer

examples/worker/getnext_broker/check_linux.sh

examples/worker/getnext_broker/check_windows.bat

examples/worker/getnext_broker/getnext_broker.cpp

receiver/src/request_handler_db_write.cpp

receiver/unittests/test_request_handler_db_writer.cpp

tests/automatic/full_chain/CMakeLists.txt

tests/automatic/full_chain/simple_chain/check_linux.sh

tests/automatic/full_chain/simple_chain/check_windows.bat

.../automatic/full_chain/simple_chain_filegen/check_linux.sh

...tomatic/full_chain/simple_chain_filegen/check_windows.bat

...c/full_chain/simple_chain_filegen_readdata/CMakeLists.txt

...c/full_chain/simple_chain_filegen_readdata/check_linux.sh

...ull_chain/simple_chain_filegen_readdata/check_windows.bat

...tic/full_chain/simple_chain_filegen_readdata/test.json.in

tests/automatic/full_chain/two_beamlines/check_linux.sh

tests/automatic/full_chain/two_beamlines/check_windows.bat

.../automatic/high_avail/broker_mongo_restart/check_linux.sh

tests/automatic/high_avail/services_restart/check_linux.sh

worker/api/cpp/src/net_client.h

worker/api/cpp/src/server_data_broker.cpp