///

/// * `self` and `origin` must either

///

/// * point to the same address, or

/// * both be *derived from* a pointer to the same [allocated object], and the memory range between

/// the two pointers must be either empty or in bounds of that object. (See below for an example.)

/// * or both be derived from an integer literal/constant, and point to the same address.

/// the two pointers must be in bounds of that object. (See below for an example.)

///

/// * The distance between the pointers, in bytes, must be an exact multiple

/// of the size of `T`.

/// let ptr1 = NonNull::new(Box::into_raw(Box::new(0u8))).unwrap();

/// let ptr2 = NonNull::new(Box::into_raw(Box::new(1u8))).unwrap();

/// let diff = (ptr2.addr().get() as isize).wrapping_sub(ptr1.addr().get() as isize);

/// // Make ptr2_other an "alias" of ptr2, but derived from ptr1.

/// let ptr2_other = NonNull::new(ptr1.as_ptr().wrapping_byte_offset(diff)).unwrap();

/// // Make ptr2_other an "alias" of ptr2.add(1), but derived from ptr1.

/// let diff_plus_1 = diff.wrapping_add(1);

/// let ptr2_other = NonNull::new(ptr1.as_ptr().wrapping_byte_offset(diff_plus_1)).unwrap();

/// assert_eq!(ptr2.addr(), ptr2_other.addr());

/// // Since ptr2_other and ptr2 are derived from pointers to different objects,

/// // computing their offset is undefined behavior, even though

/// // they point to the same address!

/// // they point to addresses that are in-bounds of the same object!

///

/// let zero = unsafe { ptr2_other.offset_from(ptr2) }; // Undefined Behavior

/// let one = unsafe { ptr2_other.offset_from(ptr2) }; // Undefined Behavior! ⚠️

/// ```

#[inline]

#[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces