text: const walk = require('./geojson-walk');
  const { performance } = require('perf_hooks');
  
  const t1 = performance.now();
  const huge = require('./assets/ne_10m_populated_places.json');
  const numFeatures = huge.features.length;
  const t2 = performance.now();
  
  let numWalked = 0;
  walk(huge, () => { numWalked++; });
  const t3 = performance.now();
  
  const loadtime = t2 - t1;
  const walktime = t3 - t2;
  
  const toSecs = (ms) => {
    return (ms / 1000).toFixed(3);
  };
  
  console.log(`Loading GeoJSON with ${numFeatures} features took ${loadtime} milliseconds (~${toSecs(loadtime)} seconds)`);
  console.log(`Walking effectively ${numWalked} features took ${walktime} milliseconds (~${toSecs(walktime)} seconds)`);
  