code: void endPass(String passName) {
      checkState(currentTracer != null, "Tracer should not be null at the end of a pass.");
      stopTracer(currentTracer, currentPassName);
      afterPass(passName);
      currentPassName = null;
      currentTracer = null;
  
      maybeRunValidityCheck();
    }
docs: Marks the end of a pass.