[#14] Add interceptors

Signed-off-by: Pavel Gross <p.gross@yadro.com>

src/FrostFS.SDK.ClientV2/Interceptors/MetricsInterceptor.cs

@@ -0,0 +1,73 @@
+using System;
+using System.Diagnostics;
+using System.Threading.Tasks;
+using FrostFS.SDK.ModelsV2;
+using Grpc.Core;
+using Grpc.Core.Interceptors;
+
+namespace FrostFS.SDK.ClientV2;
+
+public class MetricsInterceptor(Action<CallStatistics> callback) : Interceptor
+{
+    public override AsyncUnaryCall<TResponse> AsyncUnaryCall<TRequest, TResponse>(
+        TRequest request,
+        ClientInterceptorContext<TRequest, TResponse> context,
+        AsyncUnaryCallContinuation<TRequest, TResponse> continuation)
+    {
+        var call = continuation(request, context);
+
+        return new AsyncUnaryCall<TResponse>(
+            HandleUnaryResponse(call),
+            call.ResponseHeadersAsync,
+            call.GetStatus,
+            call.GetTrailers,
+            call.Dispose);
+    }
+
+    public override AsyncClientStreamingCall<TRequest, TResponse> AsyncClientStreamingCall<TRequest, TResponse>(
+        ClientInterceptorContext<TRequest, TResponse> context,
+        AsyncClientStreamingCallContinuation<TRequest, TResponse> continuation)
+    {
+         var call = continuation(context);
+
+        return new AsyncClientStreamingCall<TRequest, TResponse>(
+            call.RequestStream,
+            HandleStreamResponse(call),
+            call.ResponseHeadersAsync,
+            call.GetStatus,
+            call.GetTrailers,
+            call.Dispose);
+    }
+
+    private async Task<TResponse> HandleUnaryResponse<TResponse>(AsyncUnaryCall<TResponse> call)
+    {
+        var watch = new Stopwatch();
+        watch.Start();
+      
+        var response = await call.ResponseAsync;
+
+        watch.Stop();
+
+        var elapsed = watch.ElapsedTicks * 1_000_000/Stopwatch.Frequency;
+
+        callback(new CallStatistics { MethodName = call.ToString(), ElapsedMicroSeconds = elapsed });
+
+        return response;    
+    }
+
+    private async Task<TResponse> HandleStreamResponse<TRequest, TResponse>(AsyncClientStreamingCall<TRequest, TResponse> call)
+    {
+        var watch = new Stopwatch();
+        watch.Start();
+      
+        var response = await call.ResponseAsync;
+
+        watch.Stop();
+
+        var elapsed = watch.ElapsedTicks * 1_000_000/Stopwatch.Frequency;
+
+        callback(new CallStatistics { MethodName = call.ToString(), ElapsedMicroSeconds = elapsed });
+
+        return response;    
+    }
+}