public static UUIDSetUnmarshaller instance() {
        return INSTANCE;
    }
An unmarshaller that unmarshals sets of UUIDs as sets of
Java {@code UUID} objects.

@author Sergei Egorov
aws-java-sdk-dynamodb/src/main/java/com/amazonaws/services/dynamodbv2/datamodeling/unmarshallers/UUIDSetUnmarshaller.java