如何限制.NET中StreamReader.ReadLine()读取的字符数？

using (var reader = new StreamReader("file.txt"))
{
    char[] buffer = new char[10]; // 设置缓冲区大小
    int charsRead = 0;
    while ((charsRead = reader.Read(buffer, 0, buffer.Length)) > 0)
    {
        // 处理读取到的字符数组
        string result = new string(buffer, 0, charsRead);
    }
}

using (var reader = new StreamReader("file.txt"))
{
    char[] buffer = new char[10]; // 设置缓冲区大小
    int charsRead = 0;
    while ((charsRead = reader.ReadBlock(buffer, 0, buffer.Length)) > 0)
    {
        // 处理读取到的字符数组
        string result = new string(buffer, 0, charsRead);
    }
}

using (var reader = new StreamReader("file.txt"))
{
    string line;
    StringBuilder sb = new StringBuilder();
    int totalCharsRead = 0;
    while ((line = reader.ReadLine()) != null)
    {
        int charsToRead = Math.Min(10 - totalCharsRead, line.Length); // 设置每次读取的字符数
        sb.Append(line.Substring(0, charsToRead));
        totalCharsRead += charsToRead;
        if (totalCharsRead == 10) // 达到指定字符数，进行处理
        {
            // 处理读取到的字符串
            string result = sb.ToString();
            sb.Clear();
            totalCharsRead = 0;
        }
    }
}