Throw typed exceptions

[filipetoscano]

Current:

• Exceptions are thrown by call to EnsureSuccessStatusCode

After:

• Throw ResendException (derived) exceptions
• Based on https://www.resend.com/docs/api-reference/errors
• e.g. ResendRateLimitExceededException

[christina-de-martinez]

It looks like this was taken care of already, e.g.: #7 -- is there more to do here?

[filipetoscano]

The SDK currently throws ResendException exclusively. The idea was to throw derived exceptions (e.g. ResendRateLimitExceededException) so that calling code could trap specific exceptions as necessary.

However, a similar effect can also be accomplished with the when clause:

try
{
   await _resend.EmailSendAsync( ... );
}
catch ( ResendException ex ) when ( ex.ErrorType == ErrorType.RateLimitExceeded )
{
    Console.Error.WriteLine( "Rate limit exceeded: please wait before retrying" );
}
catch ( ResendException ex )
{
    Console.Error.WriteLine( "err: {0} - {1}", ex.ErrorType, ex.Message );
}

Having said that, a specialized ResendRateLimitExceededException could include ResendRateLimit as a property, so that the calling code can check how long it should wait before the next retry.

Console.Error.WriteLine( "Rate limit exceeded: please wait {0}s before retrying", ex.Limits?.RetryAfter );

[christina-de-martinez]

Thanks for the explanation, @filipetoscano

I took a shot at adding ResendRateLimitExceededException and using it once. I wanted to check if I'm on the right track before adding more. PR: #18

I also added an option to auto retry, since we know how long the client needs to wait before retrying. This can be disabled if users don't want this functionality.

I'm learning C# and using this as a way to practice, so if this is way off, you can just ignore me. But if it's close enough to be helpful I'd appreciate your feedback!