Method snapshot

packages/server/src/performance.rs:198–252

(
        &self,
        udid: &str,
        query: PerformanceQuery,
        foreground: Option<ForegroundProcess>,
        display_signal: DisplaySignal,
    )

    }

    pub async fn snapshot(
        &self,
        udid: &str,
        query: PerformanceQuery,
        foreground: Option<ForegroundProcess>,
        display_signal: DisplaySignal,
    ) -> Result<SimulatorPerformanceSnapshot, AppError> {
        let sampled_at = now_ms();
        let mut warnings = Vec::new();
        let ps = list_ps_processes().await?;
        let mut processes = app_processes_from_ps(udid, foreground.as_ref(), ps);
        if let Some(foreground) = foreground.as_ref() {
            ensure_foreground_process(&mut processes, foreground).await;
        }
        processes.sort_by_key(|process| (!process.is_foreground, process.process.clone()));

        let selected_pid = query
            .pid
            .or_else(|| {
                foreground
                    .as_ref()
                    .map(|process| process.process_identifier as i32)
            })
            .or_else(|| processes.first().map(|process| process.pid));

        if processes.is_empty() {
            warnings.push("No simulator app process matched this UDID yet.".to_owned());
        }

        let mut raw_samples = Vec::new();
        for process in &processes {
            raw_samples
                .push(sample_process(process.clone(), selected_pid == Some(process.pid)).await);
        }

        let selected_pid =
            selected_pid.filter(|pid| raw_samples.iter().any(|sample| sample.process.pid == *pid));
        let (current, history) = self.merge_samples(
            raw_samples,
            selected_pid,
            display_signal,
            query.history_window_ms,
        );

        Ok(SimulatorPerformanceSnapshot {
            udid: udid.to_owned(),
            sampled_at,
            selected_pid,
            foreground_process: foreground,
            processes,
            current,
            history,
            warnings,
        })
    }

    fn merge_samples(
        &self,