Could `Data` ship a "fast path" check for identity equality?

[vanvoorden (Rick van Voorden)]

@MarSe32m

Modern implementations of memcmp will exit immediately (i.e., return zero) if the pointers passed in are identical.

That actually came up in the pitch thread:

@jrose

• @David_Smith reminded me of an infamous case where this is not true: memcmp does not check whether you gave it the same pointer in both arguments, the idea being that if you need to optimize your call to memcmp, the caller should be the one to check pointer equality, because that saves the overhead of a function call!