private String pendingRequestsToString() {
      if (pendingRequests == null) {
        return "(null)";
      }
      StringBuilder sb = new StringBuilder();
      for (final Object req : pendingRequests) {
        sb.append("[");
        sb.append(req.toString());
        sb.append("]");
      }
      return sb.toString();
    }
Creates a string of the pending requests for logging or debugging.
<p>
Caller must synchronize on this grant token.

@return a string of the pending requests for logging or debugging guarded.By this
geode-core/src/main/java/org/apache/geode/distributed/internal/locks/DLockGrantor.java