WriteLineAsync不适用于Visual Studio中的分析代码覆盖率

Question

我有一个包含streamWriter.WriteLineAsync(outputLine)

的单元测试

代码部分如下所示：

using (StreamWriter streamWriter = new StreamWriter(outputFilePath))
{
    using (StreamReader streamReader = new StreamReader(filePath))
    {
        string name = string.Empty;
        while ((name = streamReader.ReadLine()) != null)
        {
            var result = this.entitySatoriIDAccessor.GetEntityAndSatoriId(name);
            foreach (Tuple<string, string, string, double> tuple in result)
            {
                string outputLine = string.Format(
                  "{0}, {1}, {2}, {3}",
                  tuple.Item1,
                  tuple.Item2,
                  tuple.Item3,
                  tuple.Item4);
                streamWriter.WriteLineAsync(outputLine);
            }
        }
    }
}

单元测试可以通过VS的“运行选定测试”运行，但如果我选择"Analyze Code Coverage For Selected Tests"，则测试将失败，并显示错误消息"The stream is currently in use by a previous operation on the stream"。我想知道为什么会发生这种情况，在VS中使用Analyze Code Coverage进行任何特殊设置？