The default Stream implementation of this method has to rent an array so it can call the overload that accepts an array, and then copy the output over. This is because the array overload is required and the span overload was only added more recently.
We can avoid the overhead of this by implementing the span overload and working with the destination span directly. Do so for all classes we have that derive from Stream, and redirect their array overload to the span overload for code reuse.
Also avoid ReadBytes calls that allocate a buffer by either updating the stream position (if not interested in the bytes), by reusing an input buffer (if interested in the bytes), or using a stackalloc buffer to avoid the allocation (for small reads).
