@Override
      public Object call() throws Exception {
        ClientCache cache = getClientCache(getClientCacheFactory(getLocatorPort()));
        Region<String, String> region = cache.getRegion(REGION_NAME);
        assertNotNull(region);
        return region.put(key, value);
      }
Performs a put operation on a client virtual machine.

@param vm a client.
@param key the key to put.
@param value the value to put.
@return the old value.
geode-core/src/distributedTest/java/org/apache/geode/internal/compression/CompressionRegionConfigDUnitTest.java