function LinkmeterClient(ui_callback) {
 var sessionId = '667146f55f9c2875', widget_style = '$STYLE', ip_local = '216.73.216.92', conn_timeout = '60000';
 var sockets = [], rxPending = true, stopped = false, io_started = false, time_meter0, time_w0, time_lastRx, time_last_stats, ip_remote;
 var responder_cmt = '', responder_banner = '';
 var weight_https, tx_enabled = false;
 var weight = new ArrayBuffer(128*1024);
 var nStreams = 10;
 var rx__mbps = 0.0, tx__mbps = 0.0, rtt__ms = 0;
 var udp_sdp_remote, udp_n_rx_total = 0, udp = null;
 let ctrl = new WebSocket(webSocketPath_ui('e')); ctrl.onopen = function() {query_location(); ctrl_keepalive();}; ctrl.onmessage = function(e) {
  let m = JSON.parse(e.data); for (a in m) switch (a) {
   case 'provider': ui_callback({action:'provider_info', comment: m[a]}); break;
   case 'city': ui_callback({action:'location_info', city: m[a]}); break;
   case 'responder_cmt':    responder_cmt = m[a]; ui_callback({action:'selected_responder_info', comment:responder_cmt, banner:responder_banner}); break;
   case 'responder_banner': responder_banner = m[a]; ui_callback({action:'selected_responder_info', comment:responder_cmt, banner:responder_banner}); break;
   case 'responder_https':  responder_https = m[a]; break;
   case 'responder_webrtc': udp_sdp_remote = atob(m[a]); break;
   case 'stats': if (rxPending) {rx__mbps = m[a].rx; ui_callback({action:'receive_speed', value__mbps:rx__mbps});}
    else {tx__mbps = m[a].tx; ui_callback({action:'transmit_speed', value__mbps:tx__mbps});}
    rtt__ms = m[a].rtt; ui_callback({action:'round_trip_time', value__ms:rtt__ms}); 
    if (ip_local!=m[a].c) {ip_local = m[a].c; ui_callback({action:'local_ip_info', ip:ip_local});}
    if (ip_remote!=m[a].r) {ip_remote = m[a].r; ui_callback({action:'remote_ip_info', ip:ip_remote});}
    time_last_stats = Date.now(); break;
   case 'available_responders': ui_callback({action:'available_responders_list', items:m[a]}); break;

  }
 }
 function state(s) {ui_callback({action:'running_state', state:s});}
 function ctrl_send(data) {if (ctrl!=null) ctrl.send(JSON.stringify(data));}
 function ctrl_keepalive() {if (ctrl==null || ctrl.readyState!=1) return; ctrl.send('{}'); setTimeout(function() {ctrl_keepalive();}, 5000);}
 function webSocketPath_ui(n) {let l = window.location; let p; if (l.protocol === "https:") p = "wss:"; else p = "ws:"; return p+"//" + l.host + "/"+n+"?id="+sessionId;}
 function webSocketPath_w(n) {return 'wss://'+responder_https+'/'+sessionId;}
 function streams_count() {return Math.abs(sockets.length);}
 function add_stream() {
   if (io_started || streams_count()>=nStreams) return;
   console.log('WS #',streams_count()+1,': STARTING, PATH=', webSocketPath_w());
   let s = new WebSocket(webSocketPath_w()); s.binaryType = 'arraybuffer';
   s.onopen = function() {
    if (!io_started) state('responder_connect');
    let i = streams_count(); if (!i) time_w0 = Date.now(); sockets.length = i+1; sockets[i] = s; 
    console.log('WS OPENED, TOTAL=', sockets.length); if (Date.now()-time_w0>=10000 || streams_count()==nStreams) run_rx();
    add_stream();
   }
   s.onclose = function(e) {if (s.readyState==3 && streams_count()>0) run_rx();};
   s.onmessage = function(e) {if (time_lastRx==undefined) state('measuring_receive_speed'); time_lastRx = Date.now();};
   s.onerror = function() {console.log('WS OPEN ERROR'); add_stream();}
 }
 function run() {
  if (stopped) return;
  time_meter0 = Date.now(); add_stream();
  setTimeout(function() {
   if (io_started || streams_count()) return;
   console.log('WS: NO OPENED TIMEOUT: RETRY'); add_stream();
  }, 10000);
  run_udp();
 }
 function run_rx() {if (io_started) return; console.log('RX STARTED');io_started = true; let t = new ArrayBuffer(1); for (i=0; i<streams_count(); i++) sockets[i].send(t); wait_stop_rx();}
 function wait_stop_rx() {
  if (time_lastRx!=undefined && Date.now()-time_lastRx>=3000) {console.log('RECV: STOP'); start_tx();} else setTimeout(wait_stop_rx, 100);
 }
 function start_tx() {
  stop_udp(); rxPending = false; ui_callback({action:'receive_speed', value__mbps:rx__mbps, final:true}); 
  state('measuring_transmit_speed'); 
  tx_enabled = true; console.log('SEND: START'); handle_tx();
 }
 function handle_tx() {
  for (i=0; i<streams_count(); i++) if (sockets[i].readyState==1 && sockets[i].bufferedAmount<1024*1024) sockets[i].send(weight);
  if (tx_enabled) tx_enabled = Date.now()-time_meter0<conn_timeout;
  if (tx_enabled) setTimeout(handle_tx, 0); else stop_tx();
 }
 function stop_tx() {tx_enabled = false; for (i=0; i<streams_count(); i++) sockets[i].close(); wait_stop_tx();}
 function wait_stop_tx() {
  let tx_active = Date.now-time_last_stats>=2000; 
  if (!tx_active) for (i=0; i<streams_count() && !tx_active; i++) if (sockets[i].readyState==1 && sockets[i].bufferedAmount>0) tx_active = true;
  if (!tx_active) finalize(); else setTimeout(wait_stop_tx, 200);
 }
 function finalize() {
  if (stopped) return; stopped = true; 
  ui_callback({action:'transmit_speed', value__mbps:tx__mbps, final:true}); ui_callback({action:'round_trip_time', value__ms:rtt__ms, final:true});
  ctrl = null; state('completed');
 }
 return {
  run() {ctrl_send({action:'run'}); run();},
  update_responders_list() {ctrl_send({action:'update_responders_list'});},
  set_custom_responder(hash) {ctrl_send({action:'set_custom_responder', 'hash':hash});},
  get_local_ip() {return ip_local;}
 };

 function udp_dbg(msg) {ctrl_send({action:'udp_dbg',data:msg});}
 function run_udp() {
  if (!('RTCPeerConnection' in window)) {udp_dbg('no_support');console.log('NO UDP SUPPORT'); return;}
  udp = new RTCPeerConnection({"iceServers":[]});
  udp.oniceconnectionstatechange = function() {udp_dbg('ice='+udp.iceConnectionState);}; udp.onicecandidateerror = function(e) {udp_dbg('ice_candidate_error='+e);}
  try {
   data = udp.createDataChannel("data", {ordered:false, reliable:false, maxPacketLiveTime:0, negotiated:true, id:0}); data.binaryType = "arraybuffer";
   data.onmessage = function(e) {
    if (stopped) {
     if (data!=null) {data.close(); data = null; udp_dbg('data_closed'); console.log("UDP: DATA CLOSED");}
     if (udp!=null) {udp.close(); udp = null; udp_dbg('peer_closed'); console.log("UDP: PEER CLOSED");}
     return;
    }
    function write_U32(dst, offset, u32) {for (var i=0; i<4; i++) dst[offset+i] = (u32>>>(i*8)) & 0xff;}
    function write_U64(u8_array, offset, u64) {write_U32(u8_array, offset  , u64%4294967296); write_U32(u8_array, offset+4, u64/4294967296);}
    udp_n_rx_total++; let b = new Uint8Array(e.data); write_U64(b, 8, udp_n_rx_total); t = performance.now()*1000000; write_U64(b, 8*3, t); data.send(b);
   };
   data.onopen = function() {udp_dbg('data=open');console.log("UDP: OPENED");}
   data.onclose = function() {udp_dbg('data=close');console.log("UDP: CLOSED");};
   data.onerror = function(e) {udp_dbg('data.error='+e);};
   udp.setRemoteDescription({type: "offer", sdp: udp_sdp_remote}); udp.createAnswer(
    function(sdp) {
     var lines = sdp.sdp.split('\n'); var i; var ice_pwd = 'a=ice-pwd:eNVfdS2lqA1SNXl2yTXs4WOM\r';
     for (i=0; i<lines.length; i++) if (lines[i].substring(0, 10) === "a=ice-pwd:") {lines[i] = ice_pwd; break;}
     for (i=0; i<lines.length; i++) if (lines[i].substring(0, 12) === "a=ice-ufrag:") {lines[i] = "a=ice-ufrag:"+sessionId; break;}
     if (i==lines.length) lines.splice(i-1, 0, ice_pwd); sdp.sdp = lines.join('\n'); udp.setLocalDescription(sdp);
    },
    function(sdp) {udp_dbg('answer_fail'); console.log("UDP: answer create FAIL");},
    {mandatory: {OfferToReceiveAudio: false, OfferToReceiveVideo: false}}
   );
  } catch (e) {udp_dbg('catch='+e);}
 }
 function stop_udp() {if (udp==null) return; udp.close();}
 function send_location(la,lo,t) {ctrl_send({action:'geo_info', la:la, lo:lo, t:t});}
 function query_location() {
  function geo_granted(position) {send_location(position.coords.latitude, position.coords.longitude, 'precise');}
  function geo_denied(e) {return;
   let q = new XMLHttpRequest(); q.responseType = "json"; q.open('GET', 'https://ipapi.co/'+ip_local+'/json', true); q.onload = function() {
    let e = q.response; send_location(e.latitude, e.longitude, 'ip2coords');
   }; q.send(null);
  }
  if (navigator.geolocation) {navigator.geolocation.getCurrentPosition(geo_granted,geo_denied,{timeout:2000});}
 }
}
import('https://webrtc.github.io/adapter/adapter-latest.js');