code: private void sendErrorMessage(Throwable t) {
          if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) {
              Tr.debug(tc, "Sending a 400 for throwable [" + t + "]");
          }
          sendErrorMessage(StatusCodes.BAD_REQUEST);
      }
docs: Send an error message when a generic throwable occurs.
  
  @param t