PsGetProcessStartKey

UINT64 __fastcall PsGetProcessStartKey(INT64 a1){
  return *(_QWORD *)(a1 + 2296) | ((unsigned __int64)KUSER_SHARED_DATA.BootId << 48);
}

Referenced by:

EtwQueryProcessTelemetryInfo
EtwpInitStateChangeInfo
EtwpWriteAppStateChangeWithStats
EtwpWriteProcessStarted
EtwpWriteUserEvent