private RegionInterestEntry readRegionInterests(String regionName,
      final @NotNull InterestType interestType,
      boolean isDurable, boolean receiveUpdatesAsInvalidates) {
    ConcurrentMap<String, RegionInterestEntry> mapOfInterest =
        getRegionToInterestsMap(interestType, isDurable, receiveUpdatesAsInvalidates);
    return mapOfInterest.get(regionName);
  }
Return the RegionInterestEntry for the given region. Create one if none exists and forRemoval
is false.

@param r specified region
@param interestType desired interest type
@param forRemoval true if calls wants one for removal
@return the entry or null if none exists and forRemoval is true.
geode-core/src/main/java/org/apache/geode/cache/client/internal/RegisterInterestTracker.java