src/vs/platform/undoRedo/common/undoRedoService.ts/ResourceEditStack/splitFutureWorkspaceElement
class ResourceEditStack:	public splitFutureWorkspaceElement(toRemove: WorkspaceStackElement, individualMap: Map<string, ResourceStackElement>): void {
		for (let j = this._future.length - 1; j >= 0; j--) {
			if (this._future[j] === toRemove) {
				if (individualMap.has(this.strResource)) {
					// gets replaced
					this._future[j] = individualMap.get(this.strResource)!;
				} else {
					// gets deleted
					this._future.splice(j, 1);
				}
				break;
			}
		}
		this.versionId++;
	}