I'm new to HealthShare. I've installed a demo using the HS.Util.Installer helper, now I'm playing with its FHIR Gateway (which is the HSFHIR namespace). When I try to create a new resource of type Patient using HTTP POST, HealthShare responses with

{
  "resourceType": "OperationOutcome",
  "issue": [
    {
      "severity": "error",
      "code": "not-supported",
      "diagnostics": "<HSFHIRErr>InteractionNotSupported",
      "details": {
        "text": "Interaction 'create' is not supported for resource type 'Patient'.

It is clear how to get the request header value with a specific name:

Class My.RestController Extends %CSP.REST
{

ClassMethod processRequest() As %Status
{
    #dim request as %CSP.Request 
    set request = %request
    set h = ##class(%REST.Impl).%GetHeader("...")
    ...    
    return $$$OK
}

But I can't figure out how to enumerate ALL the request headers (and also get all values).