code: @PUT
      public Response conditionalUpdate(final String resource)
              throws IOException {
          return execute(getResourceRequest(RequestTypeEnum.PUT, RestOperationTypeEnum.UPDATE).resource(resource));
      }
docs: Update an existing resource based on the given condition
  @param resource the body contents for the put method
  @return the response
  @see <a href="https://www.hl7.org/fhir/http.html#update">https://www.hl7.org/fhir/http.html#update</a>