Heartbeat Bundle (ping channel with no event)

{
  "resourceType" : "Bundle",
  "id" : "3d20ea4b-90dc-4d0d-b15a-c7a893389401",
  "type" : "subscription-notification",
  "timestamp" : "2020-04-17T10:24:13.1882432-05:00",
  "entry" : [{
    "fullUrl" : "urn:uuid:a5b053d4-2603-446f-ae86-f5853ac09334",
    "resource" : {
      "resourceType" : "SubscriptionStatus",
      "id" : "a5b053d4-2603-446f-ae86-f5853ac09334",
      "text" : {
        "status" : "generated",
        "div" : "<div xmlns=\"http://www.w3.org/1999/xhtml\"><p class=\"res-header-id\"><b>Generated Narrative: SubscriptionStatus a5b053d4-2603-446f-ae86-f5853ac09334</b></p><a name=\"a5b053d4-2603-446f-ae86-f5853ac09334\"> </a><a name=\"hca5b053d4-2603-446f-ae86-f5853ac09334\"> </a><a name=\"a5b053d4-2603-446f-ae86-f5853ac09334-en-AU\"> </a><p><b>status</b>: active</p><p><b>type</b>: heartbeat</p><p><b>eventsSinceSubscriptionStart</b>: 310</p><p><b>subscription</b>: <a href=\"broken-link.html\">??</a></p><p><b>topic</b>: <a href=\"broken-link.html\">http://example.org/FHIR/R5/SubscriptionTopic/admission</a></p></div>"
      },
      "status" : "active",
      "type" : "heartbeat",
      "eventsSinceSubscriptionStart" : "310",
      "subscription" : {
        "reference" : "http://example.org/FHIR/R5/Subscription/123"
      },
      "topic" : "http://example.org/FHIR/R5/SubscriptionTopic/admission"
    }
  }]
}