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.

Comece por VectorSchemaRoot#addVector e leia a discussão relacionada na issue #301. Investigue como a reorganização de FieldVectors afeta a propriedade de seus buffers subjacentes e como os VectorSchemaRoots se comportam quando são fechados. Está concluído quando a transferência de propriedade for tratada corretamente e fechar os roots não causar mais os problemas de buffer descritos.

Escrita pelo modelo de indexação a partir do texto da issue.