add read-timeout to connection execute method as the underlying thrif…

…t interface does not implement it

lib/connection.js

@@ -97,7 +97,7 @@ function escapeCQL(val) {
   if(val instanceof Buffer){
     return val.toString('hex');
   }
-  
+
   if(val instanceof uuid.UUID){
     return val.toString();
   }
@@ -366,18 +366,32 @@ Connection.prototype.authenticate = function(callback){
 Connection.prototype.execute = function(){
   var args = Array.prototype.slice.apply(arguments),
       command = args.shift(),
-      callback = args.pop();
+      callback = args.pop(),
+      timer, calledBack = false,
+      self = this;
 
   if(typeof callback !== 'function'){
     args.push(callback);
     callback = NOOP;
   }
 
+  timer = setTimeout(function(){
+    if(!calledBack){
+      callback(new Error('Read Timed Out'));
+      self._connection.connection.destroy();
+    }
+  }, this.timeout);
+
   /**
    * Processes the return results of the query
    * @private
    */
   function onReturn(err, results){
+    clearTimeout(timer);
+    if(calledBack){
+      return;
+    }
+
     if(err){
       callback(errors.create(err));
     } else {