presto-main/src/main/java/io/prestosql/execution/buffer/OutputBuffers.java/OutputBufferId/equals
class OutputBufferId:        @Override
        public boolean equals(Object o)
        {
            if (this == o) {
                return true;
            }
            if (o == null || getClass() != o.getClass()) {
                return false;
            }
            OutputBufferId that = (OutputBufferId) o;
            return id == that.id;
        }