private Set<InternalDistributedMember> getAllNormalMembers() {
    return getDistributionManager().getNormalDistributionManagerIds(); // excludes LOCATOR_DM_TYPE
  }
Note: Overriding MethodRule is only way to get {@code Object target}
geode-core/src/distributedTest/java/org/apache/geode/management/ManagementTestRule.java