static decodeFallback(bytes, encoding) {
			const characterSet = this.encodingCharacterSet(encoding);
			if (StringEncoding.isDecodeFallbackSupported(characterSet)) {
				let s = '';
				for (let i = 0, length = bytes.length; i < length; i++) {
					let h = bytes[i].toString(16);
					if (h.length < 2) {
						h = '0' + h;
					}
					s += '%' + h;
				}
				return decodeURIComponent(s);
			}
			if (characterSet.equals(CharacterSetECI.UnicodeBigUnmarked)) {
				return String.fromCharCode.apply(null, new Uint16Array(bytes.buffer));
			}
			throw new UnsupportedOperationException(`Encoding ${this.encodingName(encoding)} not supported by fallback.`);
		}
Runs a fallback for the native decoding funcion.