update narrative in the steps for the diagram: "3. Payer responds with an http transactional layer response either accepting or rejecting the transaction. The Payer  _SHOULD  return an informational OperationOutcome with the http accept response if the attachments can not be associated with a current claim or prior authorization and are being held for association with a future claim or prior authorization."_   Add additional guidance to the operation definition:   "The operation may be invoked before, at the same time as, or after the claim or pre-authorization has been supplied to the Payer."   "If the attachment is to a non-recognized existing claim or member, the server { }SHOULD{ } return an [OperationOutcome] ( http://hl7.org/fhir/operationoutcome.html ) to inform the Data Source that the attachments are being held for subsequent association to a claim or prior-authorization."   add additional guidance to theUnsolicited Workflow section:    The attachments may be submitted before, at the same time as, or after the claim or pre-authorization has been supplied to the Payer.   add example interaction with operation outcome