Add support for sending the JSON PATCH interaction to FhirClient

[ewoutkramer]

Discussed in #2217

^{Originally posted by timammons August 30, 2022}
I am trying to patch a patient in the following way, but getting an error body: must be a list of patch operation requests. Any idea why?

Code:
`static void UpdatePatientName(FhirClient fireClient, string patientID)
{
var pat = fireClient.Read($"/Patient/{patientID}");
var eTag = fireClient.LastResult.Etag;

Parameters patParams = new Parameters();
patParams.AddReplacePatchParameter("name/0/given", new HumanName().WithGiven("Beulah").WithGiven("Z"));

fireClient.RequestHeaders.IfMatch.Add(new EntityTagHeaderValue($"\"{eTag}\"", true)); 
var updatedPat = fireClient.Patch<Patient>($"{patientID}", patParams);

}`

This is the body it created, which appears to be a list of patch operation requests:
{"resourceType":"Parameters","parameter":[{"name":"operation","part":[{"name":"type","valueCode":"replace"},{"name":"path","valueString":"name/0/given"},{"name":"value","valueHumanName":{"given":["Beulah","Z"]}}]}]}

Thanks,
Tim

[mmsmits]

Refinement:

• First, add a custom Patch operation to the FhirClient, where users can define their own payload.
• Maybe add some helper methods to make JsonPatch easier. Is there an existing library for that?
• Test against a cerner sandbox (integration test). Or find out another server that supports this.
• Also create a Moq test.