docs: public long requestMemoryRevoking()
      {
          long revokedMemory = 0L;
          Runnable listener = null;
          synchronized (this) {
              if (!isMemoryRevokingRequested() && operatorMemoryContext.getRevocableMemory() > 0) {
                  memoryRevokingRequested = true;
                  revokedMemory = operatorMemoryContext.getRevocableMemory();
                  listener = memoryRevocationRequestListener;
              }
          }
          if (listener != null) {
              runListener(listener);
          }
          return revokedMemory;
      }