code: private static boolean newPojoHasNewOrRemovedFields(
  			LinkedOptionalMap<Field, TypeSerializerSnapshot<?>> fieldSerializerSnapshots,
  			PojoSerializer<?> newPojoSerializer) {
  		int numRemovedFields = fieldSerializerSnapshots.absentKeysOrValues().size();
  		int numPreexistingFields = fieldSerializerSnapshots.size() - numRemovedFields;
  
  		boolean hasRemovedFields = numRemovedFields > 0;
  		boolean hasNewFields = newPojoSerializer.getFields().length - numPreexistingFields > 0;
  		return hasRemovedFields || hasNewFields;
  	}
docs: Checks whether the new {@link PojoSerializer} has new or removed fields compared to the previous one.