finalize() {
			const sha1 = this;
			let b = sha1._buffer;
			const h = sha1._h;

			// Round out and push the buffer
			b = bitArray.concat(b, [bitArray.partial(1, 1)]);
			// Round out the buffer to a multiple of 16 words, less the 2 length words.
			for (let i = b.length + 2; i & 15; i++) {
				b.push(0);
			}

			// append the length
			b.push(Math.floor(sha1._length / 0x100000000));
			b.push(sha1._length | 0);

			while (b.length) {
				sha1._block(b.splice(0, 16));
			}

			sha1.reset();
			return h;
		}
Complete hashing and output the hash value.
@return {bitArray} The hash value, an array of 5 big-endian words. TODO