private void handleDepthDecreased(final TraceFrame frame) {
    // check if next frame depth has decreased i.e the current operation closes the parent trace
    if (currentTraceFrame != null && frame.getDepth() < lastDepth) {
      currentTrace = parentTraces.removeLast();
    }
  }
Add a trace frame to the VmTrace result object.

@param frame the current trace frame
ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/results/tracing/vm/VmTraceGenerator.java