protected override async Task <Stream> CreateContentReadStreamAsync()
        {
            MultipartContent multipartContent = this;

            try
            {
                Stream[]      streams     = new Stream[2 + multipartContent._nestedContent.Count * 2];
                StringBuilder scratch     = new StringBuilder();
                int           streamIndex = 0;
                streams[streamIndex++] = MultipartContent.EncodeStringToNewStream("--" + multipartContent._boundary + "\r\n");
                for (int contentIndex = 0; contentIndex < multipartContent._nestedContent.Count; ++contentIndex)
                {
                    HttpContent content = multipartContent._nestedContent[contentIndex];
                    streams[streamIndex++] = MultipartContent.EncodeStringToNewStream(multipartContent.SerializeHeadersToString(scratch, contentIndex, content));
                    ConfiguredTaskAwaitable <Stream> configuredTaskAwaitable = content.ReadAsStreamAsync().ConfigureAwait(false);
                    Stream stream = await configuredTaskAwaitable ?? (Stream) new MemoryStream();
                    if (!stream.CanSeek)
                    {
                        // ISSUE: reference to a compiler-generated method
                        configuredTaskAwaitable = multipartContent.\u003C\u003En__0().ConfigureAwait(false);
                        return(await configuredTaskAwaitable);
                    }
                    streams[streamIndex++] = stream;
                }
                streams[streamIndex] = MultipartContent.EncodeStringToNewStream("\r\n--" + multipartContent._boundary + "--\r\n");
                return((Stream) new MultipartContent.ContentReadStream(streams));
            }
            catch (Exception ex)
            {
                if (NetEventSource.IsEnabled)
                {
                    NetEventSource.Error((object)multipartContent, (object)ex, nameof(CreateContentReadStreamAsync));
                }
                throw;
            }
        }
        private protected async Task SerializeToStreamAsyncCore(
            Stream stream,
            TransportContext context,
            CancellationToken cancellationToken)
        {
            MultipartContent multipartContent = this;

            try
            {
                ConfiguredValueTaskAwaitable valueTaskAwaitable = MultipartContent.EncodeStringToStreamAsync(stream, "--" + multipartContent._boundary + "\r\n", cancellationToken).ConfigureAwait(false);
                await         valueTaskAwaitable;
                StringBuilder output = new StringBuilder();
                for (int contentIndex = 0; contentIndex < multipartContent._nestedContent.Count; ++contentIndex)
                {
                    HttpContent content = multipartContent._nestedContent[contentIndex];
                    valueTaskAwaitable = MultipartContent.EncodeStringToStreamAsync(stream, multipartContent.SerializeHeadersToString(output, contentIndex, content), cancellationToken).ConfigureAwait(false);
                    await valueTaskAwaitable;
                    await content.CopyToAsync(stream, context, cancellationToken).ConfigureAwait(false);

                    content = (HttpContent)null;
                }
                valueTaskAwaitable = MultipartContent.EncodeStringToStreamAsync(stream, "\r\n--" + multipartContent._boundary + "--\r\n", cancellationToken).ConfigureAwait(false);
                await valueTaskAwaitable;
                output = (StringBuilder)null;
            }
            catch (Exception ex)
            {
                if (NetEventSource.IsEnabled)
                {
                    NetEventSource.Error((object)multipartContent, (object)ex, nameof(SerializeToStreamAsyncCore));
                }
                throw;
            }
        }