* MAC differentiates between DU/eNB
* sends ITTI message to DU task for F1AP_UE_CONTEXT_RELEASE_REQ
* message is dispatched to correctly in DU_TASK
* sender correctly fills IDs and cause and sends
Connection goes until generation of RRCConnectionSetup in CU which crashes (it calls rrc_mac_config_req. For DU this should be replaced with filling DL_RRC_MESSAGE_TRANSFER