fromBits(arr) {
				const bl = bitArray.bitLength(arr);
				const byteLength = bl / 8;
				const out = new Uint8Array(byteLength);
				let tmp;
				for (let i = 0; i < byteLength; i++) {
					if ((i & 3) === 0) {
						tmp = arr[i / 4];
					}
					out[i] = tmp >>> 24;
					tmp <<= 8;
				}
				return out;
			}
Convert from a bitArray to an array of bytes.