anchor.diff:  |Resource|Base URI: http://{serverRoot}/ngsi9|HTTP verbs|
   |----|----|----|
   |   |  | POST|
  -|Notify context resource|//{notificationURI}|Generic availability notification.The expected request body is an instance of notifyContextAvailabilityRequest; the response body is an instance of notifyContextAvailabilityResponse.|
  +|Notify context resource|//{callbackURL}|Generic availability notification.The expected request body is an instance of notifyContextAvailabilityRequest; the response body is an instance of notifyContextAvailabilityResponse.|
   
   ## Terminology
   
  
positive.code: + Request (application/json)
  
          {
  "entities": [
      {
           "type": "Room",
           "isPattern": "true",
           "id": ".*"
      }
      ],
      "attributes": [
       "temperature"
      ],
      "reference": "http://localhost:8080/accumulate",
      "duration": "P1M"
   }
  
  + Response 201 (application/json)
  
      + Headers
  
              Location: /ngsi9
  
      + Body
  
              {
    "duration": "P1M",
      "subscriptionId": "52a745e011f5816465943d59"
    }
    
  ### Update Subscription to Context availability operation [POST /updateContextAvailabilitySubscription]
  
  
negative.code: 
          {
          "subscriptionId": "52a745e011f5816465943d59"
          }
  
  + Response 201 (application/json)
  
      + Headers
  
              Location: /ngsi9
  
      + Body
  
              {
              "statusCode": {
              "code": "200",
              "reasonPhrase": "OK"
              },
              "subscriptionId": "52a745e011f5816465943d59"
              }  
    
  ### Notify Context availability operation [POST /{callbackURL}]
  
  This operation is initiated by the You may create your own request using this action. It takes a JSON
  object containing a unsubscribeContextAvailabilityRequest message.
  
  + Request (application/json)
  
          {
          "subscriptionId": "52a745e011f5816465943d59",
          "contextRegistrationResponses": [
          {
              "contextRegistration": {
                  "entities": [
                      {
                          "type": "Room",
                          "isPattern": "false",
                          "id": "Room1"
                      },
                      {
                          "type": "Room",
                          "isPattern": "false",
                          "id": "Room2"
                      }
                  ],
                  "attributes": [
                      {
                          "name": "temperature",
                          "type": "float",
                          "isDomain": "false",
                          "metadatas": [
                              {
                                  "name": "accuracy",
                                  "type": "float",
                                  "value": "0.8"
                              }
                          ]
                      }
                  ],
                  "providingApplication": "http://mysensors.com/Rooms"
              }
          }
          ]
          }
  
  + Response 201 (application/json)
  
      + Headers
  
              Location: /ngsi9
  
      + Body
  
              {
              "statusCode": {
              "code": "200",
              "reasonPhrase": "OK"
              }
              }
  