presto-parquet/src/main/java/io/prestosql/parquet/Field.java/Field/Field
class Field:    protected Field(Type type, int repetitionLevel, int definitionLevel, boolean required)
    {
        this.type = requireNonNull(type, "type is required");
        this.repetitionLevel = repetitionLevel;
        this.definitionLevel = definitionLevel;
        this.required = required;
    }