public org.apache.samza.sql.avro.schemas.ComplexUnion.Builder clearNonNullableUnionValue() {
      non_nullable_union_value = null;
      fieldSetFlags()[0] = false;
      return this;
    }
Clears the value of the 'non_nullable_union_value' field
samza-sql/src/test/java/org/apache/samza/sql/avro/schemas/ComplexUnion.java