We consider that there should be a null check before dereference on Buf.

In this code, if we dereference the buffer right after calling new(), it pass null pointer to the unsafe function slice::from_raw_parts. Based on the documentation of function,

data must be non-null and aligned even for zero-length slices or slices of ZSTs.

Even though it is zero-length slice, we should ensure that the pointer is not null.

How do you think about it?