System.Net.Http.HttpHandlerToFilter.ConvertRequestAsync C# (CSharp) Метод

        private async Task<RTHttpRequestMessage> ConvertRequestAsync(HttpRequestMessage request)
        {
            RTHttpRequestMessage rtRequest = new RTHttpRequestMessage(new RTHttpMethod(request.Method.Method), request.RequestUri);

            // We can only control the Version on the first request message since the WinRT API
            // has this property designed as a filter/handler property. In addition the overall design
            // of HTTP/2.0 is such that once the first request is using it, all the other requests
            // to the same endpoint will use it as well.
            if (Interlocked.Exchange(ref _filterMaxVersionSet, 1) == 0)
            {
                RTHttpVersion maxVersion;
                if (request.Version == HttpVersionInternal.Version20)
                {
                    maxVersion = RTHttpVersion.Http20;
                }
                else if (request.Version == HttpVersionInternal.Version11)
                {
                    maxVersion = RTHttpVersion.Http11;
                }
                else if (request.Version == HttpVersionInternal.Version10)
                {
                    maxVersion = RTHttpVersion.Http10;
                }
                else
                {
                    // TODO (#7878): We need to throw an exception here similar to .NET Desktop
                    // throw new ArgumentException(SR.GetString(SR.net_wrongversion), "value");
                    //
                    // But we need to do that checking in the HttpClientHandler object itself.
                    // and we have that bug as well for the WinHttpHandler version also.
                    maxVersion = RTHttpVersion.Http11;
                }
                
                // The default for WinRT HttpBaseProtocolFilter.MaxVersion is HttpVersion.Http20.
                // So, we only have to change it if we don't want HTTP/2.0.
                if (maxVersion !=  RTHttpVersion.Http20)
                {
                    _next.MaxVersion = maxVersion;
                }
            }
            
            // Headers
            foreach (KeyValuePair<string, IEnumerable<string>> headerPair in request.Headers)
            {
                foreach (string value in headerPair.Value)
                {
                    bool success = rtRequest.Headers.TryAppendWithoutValidation(headerPair.Key, value);
                    Debug.Assert(success);
                }
            }

            // Properties
            foreach (KeyValuePair<string, object> propertyPair in request.Properties)
            {
                rtRequest.Properties.Add(propertyPair.Key, propertyPair.Value);
            }

            // Content
            if (request.Content != null)
            {
                rtRequest.Content = await CreateRequestContentAsync(request, rtRequest.Headers).ConfigureAwait(false);
            }

            return rtRequest;
        }