src/vs/workbench/api/browser/mainThreadCommands.ts/MainThreadCommands/$registerCommand
class MainThreadCommands:	$registerCommand(id: string): void {
		this._commandRegistrations.set(
			id,
			CommandsRegistry.registerCommand(id, (accessor, ...args) => {
				return this._proxy.$executeContributedCommand(id, ...args).then(result => {
					return revive(result);
				});
			})
		);
	}