Gets the buffer at @idx, ensuring it is a writable buffer.
You must make sure that @idx does not exceed the number of buffers available.
the index
the buffer at @idx in @group. The returned buffer remains valid as long as @list is valid and the buffer is not removed from the list.
1.14
See Implementation
Gets the buffer at @idx, ensuring it is a writable buffer.
You must make sure that @idx does not exceed the number of buffers available.