31:T5ae,rtts_edge = { let rtts = []; let parsings = []; let observer = new PerformanceObserver((list, obj) => { let a = list.getEntries()[0]; if (a.name === 'https://ip-echo.webmeasurements.net/') { console.log(a); let rtt = a.responseStart - a.requestStart; let parsing = a.responseEnd - a.responseStart; mutable total_bytes_rx += a.encodedBodySize; rtts.push(rtt); parsings.push(parsing); } else { // all other names (observablehq, etc) } }); observer.observe({ entryTypes: ["resource"] }); // let rtts_tcp = await Promise.all( // [ ...Array(500).keys() ].map( // _ => fetch( // `https://ip-echo.webmeasurements.net/` // ).then( // r => r.json() // ).then( // r => r.clientTcpRtt // ) // ) // ); let dirty_rtts = []; let rtts_tcp = []; for (let i of [...Array(constants().samples).keys()]) { let t0 = new Date(); let rtt_tcp = await fetch(`https://ip-echo.webmeasurements.net/`) .then(r => r.json()) .then(r => r.clientTcpRtt); dirty_rtts.push(new Date() - t0); rtts_tcp.push(rtt_tcp); } // let rtts_tcp = []; // fetch( // `https://ip-echo.webmeasurements.net/` // ).then( // r => r.json() // ).then( // r => r.clientTcpRtt // ) return { tcp: rtts_tcp, w3c: rtts, dirty: dirty_rtts, parsing: parsings }; }32:[{"id":"df0d320ddc1cb022ddec7c1ca74c8e711cdb84b295d6c5da2acc69faf0fe9037ccbaaa3d13fd017f124e2c801012d01c53cecf5d92ac1cef04e0fd27a4db8caf","href":"https://static.observableusercontent.com/files/df0d320ddc1cb022ddec7c1ca74c8e711cdb84b295d6c5da2acc69faf0fe9037ccbaaa3d13fd017f124e2c801012d01c53cecf5d92ac1cef04e0fd27a4db8caf","name":"ne_10m_populated_places_simple.json","type":"application/json","lastModified":1611408478440.547,"size":5562189}] 2f:{"title":"Web latency - headless","cells":[{"id":4722,"value":"md`# Web latency - headless`","pinned":false,"hidden":false,"mode":"ojs"},{"id":4755,"value":"md`Perform web measurements from your browser using the built-in fetch API, towards trusted servers ([RIPE Atlas Anchors](https://atlas.ripe.net/anchors/about/)).`","pinned":false,"hidden":false,"mode":"ojs"},{"id":4738,"value":"viewof button = html`

${Object.assign(html`