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.

Comienza con VectorSchemaRoot#addVector y lee la discusión relacionada en el issue #301. Investiga cómo la reorganización de FieldVectors afecta a la propiedad de sus búferes subyacentes y cómo se comportan los VectorSchemaRoots al cerrarse. Se considera terminado cuando la transferencia de propiedad se gestiona correctamente y cerrar los roots ya no provoca los problemas de búfer descritos.

Escrito por el modelo de indexación a partir del texto del issue.