major revamp of http client functionalit

lib/session/rest-call-session.js

@@ -2,6 +2,11 @@ const CallSession = require('./call-session');
 const {CallStatus} = require('../utils/constants');
 const moment = require('moment');
 
+/**
+ * @classdesc Subclass of CallSession.  This represents a CallSession that is
+ * created for an outbound call that is initiated via the REST API.
+ * @extends CallSession
+ */
 class RestCallSession extends CallSession {
   constructor({logger, application, srf, req, ep, tasks, callInfo}) {
     super({
@@ -19,12 +24,19 @@ class RestCallSession extends CallSession {
     this._notifyCallStatusChange({callStatus: CallStatus.Trying, sipStatus: 100});
   }
 
+  /**
+   * Stores the sip dialog that is created when the far end answers.
+   * @param {Dialog} dlg - sip dialog
+   */
   setDialog(dlg) {
     this.dlg = dlg;
     dlg.on('destroy', this._callerHungup.bind(this));
     dlg.connectTime = moment();
   }
 
+  /**
+   * This is invoked when the called party hangs up, in order to calculate the call duration.
+   */
   _callerHungup() {
     const duration = moment().diff(this.dlg.connectTime, 'seconds');
     this.emit('callStatusChange', {callStatus: CallStatus.Completed, duration});