EFCore.Cosmos - RequestCharge

[espray]

Finding an operations RUs is vital for optimizing cosmos db
@AndriySvyryd how can I retrieve the RequestCharge for an operation?

-- Describe the solution you'd like --
Ability to add a CosmosRequestHandler. This can be done by CosmosClientOptions.CustomHandlers.Add(handler)

public class LoggingHandler : CosmosRequestHandler
{
  public override async Task<CosmosResponseMessage> SendAsync(CosmosRequestMessage request, CancellationToken cancellationToken)
  {
    Console.WriteLine($"{request.Method.Method} - {request.RequestUri.ToString()}");
    CosmosResponseMessage response = await base.SendAsync(request, cancellationToken);
    Console.WriteLine("Operation done");
    Console.WriteLine((int)response.StatusCode);
    return response;
  }
}

https://docs.microsoft.com/en-us/dotnet/api/microsoft.azure.cosmos.cosmosclientoptions.customhandlers?view=azure-dotnet#Microsoft_Azure_Cosmos_CosmosClientOptions_CustomHandlers

https://docs.microsoft.com/en-us/dotnet/api/microsoft.azure.cosmos.fluent.cosmosclientbuilder.addcustomhandlers?view=azure-dotnet#Microsoft_Azure_Cosmos_Fluent_CosmosClientBuilder_AddCustomHandlers_Microsoft_Azure_Cosmos_RequestHandler___

https://docs.microsoft.com/en-us/dotnet/api/microsoft.azure.cosmos.requesthandler?view=azure-dotnet

[ajcvickers]

Duplicate of #17298