/// <summary>
        /// 读取为二进制数组并转换为指定的编码
        /// </summary>
        /// <param name="httpContent"></param>
        /// <param name="dstEncoding">目标编码</param>
        /// <exception cref="ArgumentException"></exception>
        /// <returns></returns>
        public static async Task <byte[]> ReadAsByteArrayAsync(this HttpContent httpContent, Encoding dstEncoding)
        {
            var encoding  = httpContent.GetEncoding();
            var byteArray = await httpContent.ReadAsByteArrayAsync().ConfigureAwait(false);

            return(encoding.Equals(dstEncoding)
                ? byteArray
                : Encoding.Convert(encoding, dstEncoding, byteArray));
        }