@Override
  public Object executeOn(ServerLocation server, Op op) {
    authenticateIfRequired(server, op);
    return executor.executeOn(server, op);
  }
Execute the given op on the given server.

@param server the server to do the execution on
@param op the operation to execute
@return the result of execution if any; null if not
geode-core/src/main/java/org/apache/geode/cache/client/internal/PoolImpl.java