append_region

Description:

[ DestroysInstance ]
public Buffer append_region (owned Buffer buf2, ssize_t offset, ssize_t size)

Appends size bytes at offset from buf2 to this.

The result buffer will contain a concatenation of the memory of this and the requested region of buf2.

this	the first source Buffer to append.
buf2	the second source Buffer to append.
offset	the offset in `buf2`
size	the size or -1 of `buf2`

the new Buffer that contains the memory of the two source buffers.