src/vs/workbench/api/common/extHostCustomEditors.ts/CustomDocumentStoreEntry/getEdit
class CustomDocumentStoreEntry:	private getEdit(editId: number): vscode.CustomDocumentEditEvent {
		const edit = this._edits.get(editId, 0);
		if (!edit) {
			throw new Error('No edit found');
		}
		return edit;
	}