BufferListFunc

A function that will be called from @foreach.

The buffer field will point to a the reference of the buffer at idx.

When this function returns true, the next buffer will be returned. When false is returned, @foreach will return.

When buffer is set to null, the item will be removed from the bufferlist. When buffer has been made writable, the new buffer reference can be assigned to buffer. This function is responsible for unreffing the old buffer when removing or modifying.

Parameters:

buffer	pointer to the buffer
idx	the index of buffer
user_data	user data passed to @foreach

Returns:

false when @foreach should stop