VerifyModel.cs

        public async Task Verify()
        {
            var result = await PickAndShow(PickOptions.Default);
            this.FileName = result.FullPath;

            using (var client = new HttpClient())
            {
                client.DefaultRequestHeaders.CacheControl = new CacheControlHeaderValue { NoCache = true, };
                client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", this.Token);
                using (var multipartContent = new MultipartFormDataContent())
                {
                    using (var fileContent = new StreamContent(File.OpenRead(this.FileName)))
                    {
                        fileContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data")
                        {
                            Name = "vein",
                            FileName = Path.GetFileName(this.FileName),
                        };
                        fileContent.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
                        multipartContent.Add(fileContent);
                        using (var response = await client.PostAsync(@"https://apigateway.research.global.fujitsu.com/vlcb/research/verify-match", multipartContent))
                        {
                            if (response.IsSuccessStatusCode)
                            {
                                // リクエストが成功した場合の処理
                                this.Response = "Success";
                            }
                            else
                            {
                                // リクエストが失敗した場合の処理
                                this.Response = response.StatusCode.ToString();
                            }
                        }
                    }
                }
            }
        }