Suggestion: Add FileSaveCancelledException or IsCancelled property to FileSaverResult for clean cancellation handling

[RaresOP]

One issue I've encountered while working withFileSaver.SaveAsync(...)is handling user-initiated cancellations. Currently, if the user cancels the save dialog, the returned FileSaverResult simply contains a generic Exception, and we have to inspect the exception message (e.g., looking for "Operation cancelled") to detect this scenario. This is brittle and not very clean.

I’d like to suggest one or both of the following enhancements:

1. Introduce a specific FileSaveCancelledException that can be caught explicitly.
2. Add an IsCancelled boolean property to the FileSaverResult type.

Example:

public record FileSaverResult(string? FilePath, Exception? Exception)
{
    public bool IsSuccessful => Exception is null;
    public bool IsCancelled => Exception is FileSaveCancelledException;
}

This would allow developers to distinguish between:

• A failure (e.g., disk issues, permission errors)
• A user cancellation (which is not really an error)

Happy to submit a PR if this change sounds acceptable.