Key points:

• The second argument to slice::from_raw_parts is the number of elements, not bytes! This example demonstrates unexpected behavior by reading past the end of one array and into another.
• This is undefined behavior because we’re reading past the end of the array that the pointer was derived from.
• log_public_key should be unsafe, because pk_ptr must meet certain prerequisites to avoid undefined behaviour. A safe function which can cause undefined behaviour is said to be unsound. What should its safety documentation say?
• The standard library contains many low-level unsafe functions. Prefer the safe alternatives when possible!
• If you use an unsafe function as an optimization, make sure to add a benchmark to demonstrate the gain.