src/vs/editor/common/core/textChange.ts/TextChangeCompressor/_splitCurr
class TextChangeCompressor:	private static _splitCurr(edit: TextChange, offset: number): [TextChange, TextChange] {
		const preText = edit.oldText.substr(0, offset);
		const postText = edit.oldText.substr(offset);

		return [
			new TextChange(
				edit.oldPosition,
				preText,
				edit.newPosition,
				edit.newText
			),
			new TextChange(
				edit.oldPosition + offset,
				postText,
				edit.newEnd,
				''
			)
		];
	}