Pool SeekableInputStreams in ParquetFileReader

If https://issues.apache.org/jira/browse/PARQUET-1982 goes through, then we could allow parallel reading of row groups with a pool of SeekableInputStreams. This would significantly boost performance for applications that read data at random positions from a large file.

I've already developed a patch that would enable this functionality. I will link the merge request in the next few days.

Is there a related ticket that i have overlooked?

**Reporter**: [Felix Schmalzel](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=fschmalzel) / @fschmalzel

_{**Note**: *This issue was originally created as [PARQUET-1983](https://issues.apache.org/jira/browse/PARQUET-1983). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}

Commencez par examiner PARQUET-1982 et l’implémentation existante de ParquetFileReader afin de comprendre le prérequis et la gestion actuelle des streams. Le travail est considéré comme terminé lorsque les lectures parallèles de groupes de lignes sont activées via un pool de SeekableInputStreams, avec validation des performances pour les lectures à des positions aléatoires.

Rédigé par le modèle d'indexation à partir du texte de l'issue.