added logging on connection open/close

lib/mongodb/connection/connection.js

@@ -84,14 +84,19 @@ Connection.prototype.start = function() {
     this.writeSteam.on("close", closeHandler(this));
     // Start socket
     this.connection.connect(this.socketOptions.port, this.socketOptions.host);
+    if(this.logger != null && this.logger.doDebug){
+      this.logger.debug("opened connection", this.socketOptions);
+    }
   } else {
     // Create new connection instance
     if(!this.domainSocket) {
       this.connection = net.createConnection(this.socketOptions.port, this.socketOptions.host);      
     } else {
       this.connection = net.createConnection(this.socketOptions.host);            
     }
-
+    if(this.logger != null && this.logger.doDebug){
+      this.logger.debug("opened connection", this.socketOptions);
+    }
     // Set options on the socket
     this.connection.setTimeout(this.socketOptions.connectTimeoutMS != null ? this.socketOptions.connectTimeoutMS : this.socketOptions.timeout);
     // Work around for 0.4.X
@@ -161,6 +166,9 @@ Connection.prototype.close = function() {
   this.connection.on("error", function() {})
   // destroy connection
   this.connection.destroy();
+  if(this.logger != null && this.logger.doDebug){
+    this.logger.debug("closed connection", this.connection);
+  }
 }
 
 // Reset all handlers