src/vs/workbench/api/browser/mainThreadDocuments.ts/BoundModelReferenceCollection/add
class BoundModelReferenceCollection:	add(uri: URI, ref: IReference<any>, length: number = 0): void {
		// const length = ref.object.textEditorModel.getValueLength();
		let handle: any;
		let entry: { uri: URI, length: number, dispose(): void };
		const dispose = () => {
			const idx = this._data.indexOf(entry);
			if (idx >= 0) {
				this._length -= length;
				ref.dispose();
				clearTimeout(handle);
				this._data.splice(idx, 1);
			}
		};
		handle = setTimeout(dispose, this._maxAge);
		entry = { uri, length, dispose };

		this._data.push(entry);
		this._length += length;
		this._cleanup();
	}