How 'other' can be used for future resources - in this case referral

Raw JSON

{
  "Other":{
    "extension":[
      {
        "url":{
          "value":"http://example.org/do-not-use/fhir-extensions/referral#referredForService"
        },
        "isModifier":{
          "value":true
        },
        "valueCodeableConcept":{
          "coding":[
            {
              "system":{
                "value":"http://snomed.info/sct"
              },
              "code":{
                "value":"11429006"
              },
              "display":{
                "value":"Consultation"
              }
            }
          ]
        }
      },
      {
        "url":{
          "value":"http://example.org/do-not-use/fhir-extensions/referral#requestingPractitioner"
        },
        "valueResource":{
          "type":{
            "value":"Practitioner"
          },
          "reference":{
            "value":"practitioner/@f201"
          },
          "display":{
            "value":"Dokter Bronsig"
          }
        }
      },
      {
        "url":{
          "value":"http://example.org/do-not-use/fhir-extensions/referral#targetDate"
        },
        "isModifier":{
          "value":true
        },
        "valuePeriod":{
          "start":{
            "value":"2013-04-01"
          },
          "end":{
            "value":"2013-04-15"
          }
        }
      },
      {
        "url":{
          "value":"http://example.org/do-not-use/fhir-extensions/referral#status"
        },
        "isModifier":{
          "value":true
        },
        "valueCode":{
          "value":"complete"
        }
      },
      {
        "url":{
          "value":"http://example.org/do-not-use/fhir-extensions/referral#notes"
        },
        "valueString":{
          "value":"The patient had fever peaks over the last couple of days. He is worried about these peaks."
        }
      },
      {
        "url":{
          "value":"http://example.org/do-not-use/fhir-extensions/referral#fulfillingEncounter"
        },
        "valueResource":{
          "type":{
            "value":"Encounter"
          },
          "reference":{
            "value":"encounter/@f201"
          }
        }
      }
    ],
    "text":{
      "status":{
        "value":"generated"
      },
      "div":"<div>\n      <p><b>Patient:<\/b>Roel<\/p>\n      <p><b>Requestor:<\/b>Dokter Bronsig<\/p>\n      <p><b>Type:<\/b>Consultation<\/p>\n      <p><b>Target Date:<\/b>April 1 - April 31<\/p>\n      <p>COMPLETED<\/p>\n      <b>The patient had fever peaks over the last couple of days. He is worried about these peaks.<\/b>\n    <\/div>"
    },
    "code":{
      "coding":[
        {
          "system":{
            "value":"http://hl7.org/fhir/other-resource-type"
          },
          "code":{
            "value":"REFERRAL"
          }
        }
      ]
    },
    "subject":{
      "type":{
        "value":"Patient"
      },
      "reference":{
        "value":"patient/@f201"
      },
      "display":{
        "value":"Roel"
      }
    }
  }
}