/// <summary>
/// Open the named file asynchronously for reading.
/// </summary>
/// <exception cref="FileNotFoundException">Throws if the file is not found.</exception>
/// <remarks>
/// Unlike <see cref="TryOpenReadOnly"/> this function throws an exception if the file is missing.
/// </remarks>
public static StreamWithLength OpenReadOnly(this IAbsFileSystem fileSystem, AbsolutePath path, FileShare share)
{
var stream = fileSystem.TryOpenReadOnly(path, share);
if (stream == null)
{
throw new FileNotFoundException($"The file '{path}' does not exist.");
}
return(stream.Value);
}