@Override
  public Execution onServers(Pool pool, String... groups) {
    if (pool == null) {
      throw new FunctionException(
          String.format("%s passed is null", "Pool instance "));
    }

    if (pool.getMultiuserAuthentication()) {
      throw new UnsupportedOperationException();
    }

    return new ServerFunctionExecutor(pool, true, groups);
  }
use when the optimization to execute onMember locally is not desired.
geode-core/src/main/java/org/apache/geode/internal/cache/execute/InternalFunctionExecutionServiceImpl.java