[perf] Add all properties to the socket in the constructor (#488)

Author: Tom Atkinson

lib/socket.js

@@ -72,6 +72,7 @@ function Socket (uri, opts) {
   this.transports = opts.transports || ['polling', 'websocket'];
   this.readyState = '';
   this.writeBuffer = [];
+  this.prevBufferLen = 0;
   this.policyPort = opts.policyPort || 843;
   this.rememberUpgrade = opts.rememberUpgrade || false;
   this.binaryType = null;
@@ -100,6 +101,16 @@ function Socket (uri, opts) {
     }
   }
 
+  // set on handshake
+  this.id = null;
+  this.upgrades = null;
+  this.pingInterval = null;
+  this.pingTimeout = null;
+
+  // set on heartbeat
+  this.pingIntervalTimer = null;
+  this.pingTimeoutTimer = null;
+
   this.open();
 }