src/vs/editor/common/tokens/contiguousTokensEditing.ts/ContiguousTokensEditing/append
class ContiguousTokensEditing:	public static append(lineTokens: Uint32Array | ArrayBuffer | null, _otherTokens: Uint32Array | ArrayBuffer | null): Uint32Array | ArrayBuffer | null {
		if (_otherTokens === EMPTY_LINE_TOKENS) {
			return lineTokens;
		}
		if (lineTokens === EMPTY_LINE_TOKENS) {
			return _otherTokens;
		}
		if (lineTokens === null) {
			return lineTokens;
		}
		if (_otherTokens === null) {
			// cannot determine combined line length...
			return null;
		}
		const myTokens = toUint32Array(lineTokens);
		const otherTokens = toUint32Array(_otherTokens);
		const otherTokensCount = (otherTokens.length >>> 1);

		const result = new Uint32Array(myTokens.length + otherTokens.length);
		result.set(myTokens, 0);
		let dest = myTokens.length;
		const delta = myTokens[myTokens.length - 2];
		for (let i = 0; i < otherTokensCount; i++) {
			result[dest++] = otherTokens[(i << 1)] + delta;
			result[dest++] = otherTokens[(i << 1) + 1];
		}
		return result.buffer;
	}