Is there are way to verify the request object passed to HttpClient.PostAsJsonAsync. The request object is constructed inside the method to be unit tested. Therefore I need to verify that the request object is constructed with correct values.

I tried the following and I am expecting to verify the searchrequest object by comparing the values as shown below
` public void Test(){

      //Arrange


      //ACT
      await _myservice.someMethodToTest(criteria);


      handlerMock.Protected().Verify(
     "SendAsync",
     Times.Exactly(1), // we expected a single external request
     ItExpr.Is<HttpRequestMessage>(req =>
        req.Method == HttpMethod.Post  // we expected a POST request
       
     ),
     ItExpr.IsAny<CancellationToken>(),
     ItExpr.Is<SearchRequest>(r => r.PublishedDateStart == publishedDateStart)   // this doesn't work       

    );  
    }


   //Method to be tested
   public void someMethodToTest(Criteria criteria){
         
     // build some complext request from criteria
     var searchRequest = new searchRequest{
      }
    var searchResponse = await httpClient.PostAsJsonAsync(url, searchRequest);

   //other code
   }``