/// <summary>

        /// 返回mp4 兼容苹果

        /// </summary>

        /// <param name="context"></param>

        /// <param name="filePath"></param>

        private void CreateVideoResponse(HttpContext context, string filePath)

        {

            var reqRange = context.Request.Headers["Range"];

            string[] reqBlockRange = null;

            if (!string.IsNullOrEmpty(reqRange))

            {

                reqBlockRange = reqRange.Replace("bytes=", "").Split(new[] { "-"},StringSplitOptions.RemoveEmptyEntries);

                context.Response.StatusCode = ;

                context.Response.AddHeader("status", "");

            }

            using (var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))

            using (var reader = new BinaryReader(stream))

            {

                long fileSize = stream.Length;

                long startPosition = ;

                long partialSize = fileSize;

                if (reqBlockRange != null)

                {
　　　　　　　　　　　　//safari

                    startPosition = Convert.ToInt64(reqBlockRange[]);

                    if(reqBlockRange.Length > )

                    {

                        long endPosition = fileSize;

                        if (long.TryParse(reqBlockRange[], out endPosition))

                        {

                            partialSize = endPosition - startPosition + ;

                        }

                    }else

                    {
　　　　　　　　　　　　　　// chrome 等

                        partialSize = fileSize - startPosition;

                    }

                }

                byte[] buffer = new byte[(int)partialSize];

                reader.BaseStream.Seek(startPosition, SeekOrigin.Begin);

                reader.Read(buffer, , (int)partialSize);

                context.Response.AddHeader("accept-ranges", "bytes");

                context.Response.AddHeader("access-control-allow-methods", "HEAD, GET, OPTIONS");

                context.Response.AddHeader("cache-control", "public, max-age=30726563");

                context.Response.ContentType = "video/mp4";

                context.Response.Cache.SetLastModified(DateTime.Now);

                context.Response.AddHeader("Connection", "keep-alive");

                context.Response.AddHeader("content-range", $"bytes {startPosition}-{startPosition + partialSize-1 }/{fileSize}");

                context.Response.AddHeader("Content-Length", $"{partialSize}");

                context.Response.BinaryWrite(buffer);

            }

        }