src/vs/editor/common/model/textModelTokens.ts/TextModelTokenization/tokenizeViewport
class TextModelTokenization:	public tokenizeViewport(startLineNumber: number, endLineNumber: number): void {
		const builder = new ContiguousMultilineTokensBuilder();
		this._tokenizeViewport(builder, startLineNumber, endLineNumber);
		this._tokenizationPart.setTokens(builder.finalize(), this._isTokenizationComplete());
	}