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.

从 VectorSchemaRoot#addVector 开始，并阅读 issue #301 中的相关讨论。调查重新排列 FieldVectors 如何影响其底层缓冲区的所有权，以及 VectorSchemaRoots 在关闭时的行为。完成的标准是正确处理所有权转移，并且关闭 roots 不再导致所描述的缓冲区问题。

由索引模型根据 Issue 内容生成。