StreamReader.ReadToEnd with maximum length

ReadToEnd.cs

public static string ReadToEnd(this StreamReader reader, int maximumCharacters)
{
	var builder = new System.Text.StringBuilder();
	while (true)
	{
		var line = reader.ReadLine();
		if (line == null)
			break;

		if (builder.Length + line.Length > maximumCharacters)
		{
			line = line.Substring(0, maximumCharacters - builder.Length - Environment.NewLine.Length);
			builder.AppendLine(line);
			break;
		}
		builder.AppendLine(line);
	}
	return builder.ToString();
}