Managing ownership in VectorSchemaRoot#addVector, recent changes miss the main fault.

A recent change in VectorSchemaRoot#addVector provided a simple improvement, but completely misses a major shortcoming of this routine and, almost certainly, others like it. Based on the interest in that issue (#301), this issue might be of interest to @axreldable and @jbonofre.

One cannot change the `FieldVector`s belonging to `VectorSchemaRoot`s by simply rearranging the elements of their `List`s without considering the ownership of their underlying buffers. This can cause various problems, particularly when `VectorSchemaRoot`s are closed. This is why `TransferPair` exists.

I would probably need some help with improving this as I'm quite new to using Apache Arrow (and very new to using GitHub). But I have written a possibly improved implementation if this would be of interest and would be open to collaborating on rectifying this bug.

Commencez par VectorSchemaRoot#addVector et consultez la discussion associée dans l’issue #301. Examinez comment la réorganisation des FieldVectors affecte la propriété de leurs buffers sous-jacents et comment les VectorSchemaRoots se comportent lorsqu’ils sont fermés. Le travail est terminé lorsque le transfert de propriété est géré correctement et que la fermeture des roots ne provoque plus les problèmes de buffer décrits.

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