Calculate resource download time

download-time.js

/**
 * Returns download time from server
 * 
 * @param {number} cwnd - Initial Congestion Window size
 * @param {number} rtt - Roundtrip Time in Milliseconds
 * @param {number} packetSize - Packet Size in Bytes
 * @param {number} totalSize - Total Transfer Size in Bytes
 * @return {number} time - Download Time in Milliseconds
 */
function downloadTime(cwnd, rtt, packetSize, totalSize) {
  var segments = totalSize / packetSize;
  return rtt * Math.ceil( Math.log2(segments / cwnd) );
}