for (Map.Entry<Long, Map<Long, TestCaseRegion>> classEntry : index.entrySet()) {
Long classId = classEntry.getKey();
Map<Long, TestCaseRegion> regions = classEntry.getValue();
indexOutput.writeLong(classId, true);
indexOutput.writeInt(regions.size(), true);
for (Map.Entry<Long, TestCaseRegion> testCaseEntry : regions.entrySet()) {
long id = testCaseEntry.getKey();
TestCaseRegion region = testCaseEntry.getValue();