/// <summary>
 /// Instantiates SubscribeRequest with the parameterized properties
 /// </summary>
 /// <param name="subscriptionName">The name for the subscription to be created.</param>
 /// <param name="endpoint">The subscribe endpoint.</param>
 /// <param name="strategy">The NotifyStrategy for the subscription.</param>
 /// <param name="contentFormat">The NotifyContentFormat for the subscription.</param>
 public SubscribeRequest(string subscriptionName,
                         string endpoint,
                         SubscriptionAttributes.NotifyStrategy strategy,
                         SubscriptionAttributes.NotifyContentFormat contentFormat)
     : this(subscriptionName, endpoint, null, strategy, SubscriptionAttributes.NotifyContentFormat.XML)
 {
 }
 /// <summary>
 /// Instantiates SubscribeRequest with the parameterized properties
 /// </summary>
 /// <param name="subscriptionName">The name for the subscription to be created.</param>
 /// <param name="endpoint">The subscribe endpoint.</param>
 /// <param name="filterTag">The subscribe filterTag.</param>
 /// <param name="strategy">The NotifyStrategy for the subscription.</param>
 /// <param name="contentFormat">The NotifyContentFormat for the subscription.</param>
 public SubscribeRequest(string subscriptionName,
                         string endpoint, string filterTag,
                         SubscriptionAttributes.NotifyStrategy strategy,
                         SubscriptionAttributes.NotifyContentFormat contentFormat)
 {
     _subscriptionName = subscriptionName;
     _endpoint         = endpoint;
     _filterTag        = filterTag;
     _strategy         = strategy;
     _contentFormat    = contentFormat;
 }