@CliCommand(value = ALTER_MOCK_REGION_EXTENSION)
  @ResourceOperation(resource = Resource.CLUSTER, operation = Operation.READ)
  public Result alterMockRegionExtension(
      @CliOption(key = OPTION_REGION_NAME, mandatory = true) final String regionName,
      @CliOption(key = OPTION_VALUE, mandatory = true) final String value) {
    return executeFunctionOnAllMembersTabulateResultPersist(
        AlterMockRegionExtensionFunction.INSTANCE, true,
        AlterMockRegionExtensionFunction.toArgs(regionName, value));
  }
Alters a {@link MockRegionExtension} on the given <code>regionName</code>.

@param regionName {@link Region} name on which to create {@link MockRegionExtension} .
@param value {@link String} value to set on {@link MockRegionExtension#setValue(String)}.
@return {@link Result}
@since GemFire 8.1
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/extension/mock/MockExtensionCommands.java