title: adding many polyLines in R leaflet
body: <p>Is there a way to add all my poly lines at once. Doing it the way below is very slow...</p>
  
  <p>At the moment, I'm doing it through a for loop as follows:</p>
  
  <pre><code>leafletProxy("mainMap") %&gt;% 
            addPolylines(lng = currentGeoData[i,c("CustLon","SerCenterLon")], 
                         lat = currentGeoData[i,c("CustLat","SerCenterLat")],
                         color = "red")
  </code></pre>
  
  <p>so each time my <code>lng</code>variable is vector of length 2 and my <code>lat</code> variable is the same.</p>