private void putString(Region<Object, Object> region, List<ExpectedValues> expected) {
    String key = "keyString";
    String value = "this is a string";
    region.put(key, value);
    expected.add(new ExpectedValues(value, value.length() * 2, "java.lang.String", -1,
        getMemoryAddress(region, key), 1, 0, false, true));
  }
Returns -1 if m1 is missing a key in m2, 1 if m2 is missing a key in m1, or 0 is they contain
the exact same keys.

@throws NullPointerException if either c1 or c2 is null
geode-core/src/integrationTest/java/org/apache/geode/internal/offheap/OffHeapValidationJUnitTest.java