src/vs/workbench/contrib/debug/browser/debugSession.ts/DebugSession/stepIn
class DebugSession:	async stepIn(threadId: number, targetId?: number, granularity?: DebugProtocol.SteppingGranularity): Promise<void> {
		if (!this.raw) {
			throw new Error(localize('noDebugAdapter', "No debugger available, can not send '{0}'", 'stepIn'));
		}

		this.setLastSteppingGranularity(threadId, granularity);
		await this.raw.stepIn({ threadId, targetId, granularity });
	}