Validate unsafe blocks are actually giving us a performance improvement

[wesleywiser]

We have various places in measureme where we do low-level unsafe operations for efficiency. Example:

measureme/measureme/src/raw_event.rs

Lines 103 to 113 in 8d2d4fd

	#[cfg(target_endian = "little")]
	{
	let raw_event_bytes: &[u8] = unsafe {
	std::slice::from_raw_parts(
	self as *const _ as *const u8,
	std::mem::size_of::<RawEvent>(),
	)
	};
	bytes.copy_from_slice(raw_event_bytes);
	}

We should validate that these places are actually improving performance over their safe counterparts.

[workingjubilee]

Not exactly the same but other experiences like BurntSushi/fst@7440fa7 suggest that moving from unsafe to safe code for byte-level conversions like these may not provide a measurable (heh) penalty.