There is no option to set ParquetWriterConfig when create new ParquetSink instance

There is no params to set ParquetWriterConfig when create new ParquetSink instance.
I couldn't set it after created.
Because some variables which for it were defined as val. And almost components were in closure.
How can I do that? Or, when you change this?

Look at the ParquetSink class and its constructor to see how ParquetWriterConfig is currently handled. The issue mentions that variables are defined as 'val' and components are in a closure, so examine the internal structure and dependencies. Determine where configuration can be injected or modified, then check for existing tests related to ParquetSink to understand the expected behavior.

索引モデルが issue の本文から書いたものです。