Question on parquet-protobuf and parquet-pig

Hi,

I have a question about protobuf to parquet conversion.
I have a message like this (simplified) :
```Java

message MyMessage {
repeated string language = 1;
}
```

parquet-protobuf convert it to the following schema :

```Java
message MyMessage {
repeated binary language (UTF8);
}
```

But, according to TestPigSchameConverter.java, the correct schema should be :

```Java
message MyMessage {
optional group language (LIST) {
repeated binary value (UTF8);
}
}
```

Language is an optional list of language, i want to store zero or more language.

Who have the correct schema for my case ? parquet-protobuf or parquet-pig ?

**Reporter**: [Christian Nguyen Van Than](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=cnguyen@nextperf.com)

_{**Note**: *This issue was originally created as [PARQUET-354](https://issues.apache.org/jira/browse/PARQUET-354). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}

将 protobuf 转换行为与 TestPigSchameConverter.java 中的预期 schema 进行比较，首先了解 parquet-protobuf 和 parquet-pig 如何表示重复的 string 字段。确定对于零个或更多值，这些 schema 是否存在错误差异，并记录一个可复现的结论或 test，以解决哪种表示是正确的。

由索引模型根据 Issue 内容生成。