Equivalent to the appropriate llvm.memcpy.p0i8.0i8.* intrinsic, with a size of count * size_of::<T>() and an alignment of align_of::<T>().

This intrinsic does not have a stable counterpart.

Safety

The safety requirements are consistent with copy_nonoverlapping while the read and write behaviors are volatile, which means it will not be optimized out unless _count or size_of::<T>() is equal to zero.