PolicyRecordingBot - Get Caller and Callee

When the recording bot receives a call, how can you tell which participant is the caller and which is the recipient?

The notifications that arrive during a call give information about participants as they are added and removed, but I can't see how to determine which one is the initiator of the call.

The only place I can see a "Caller" and a "Callee" is in the "botData" part of the initial invite message (example below - guids and numbers removed - "+44xxxxxxxxxx" is the phone number making the call).

"applicationMetadata": {
  "botData": {
    "callId": "xxxxxxx (guid) xxxxxxx",
    "mediaHostedRegion": "EUWE",
    "user": {
      "participationMethod": "Callee"
    },
    "otherSideUser": {
      "id": "4:+44xxxxxxxxxx",
      "participantId": "xxxxxxx (guid) xxxxxxx",
      "tenantId": "00000000-0000-0000-0000-000000000000",
      "participationMethod": "Caller"
    },
    "inviteReasons": [
      "ComplianceRecording"
    ],
    "policyIdentifier": "TeamsComplianceRecordingPolicy=Tenant:ComplianceRecordingPolicy",
    "otherRecorders": [],
    "pairedRecorders": []
  }
}

These properties don't appear to be available in the 'Call' object directly.

The only way I can see to get this data is by using call.Resource.AdditionalData["applicationMetadata"] and parsing the JSON inside it.

Am I doing this properly?

Start with the initial invite message's applicationMetadata.botData and compare it with the Call object and call.Resource.AdditionalData. Check the sample's handling of participant notifications and determine whether caller and callee are exposed through a supported API surface. Done means establishing a documented, supported way to identify both participants or clearly recording that the requested properties are unavailable.