# Shifts the content of the buffer by `len` bytes to the left, starting at `from`
	#
	# Internal only, does not modify _byte_length or length, this is the caller's responsability
	private fun lshift_bytes(from: Int, len: Int) do
		var it = _items
		it.copy_to(it, _byte_length - from, from, from - len)
	end