Incorrect verb mapped to default verb

When verb is not specified it is mapped to default verb, when default verb specified. Awesome!

But I recently found that even a incorrect verb is provided it is mapped to default verb as well.

So how could throw an exception to user notifying that incorrect verb is given, while there is a default verb as well. I want to allow empty verb as well.

Empty verb => Default Verb
Incorrect verb => call **with no parsed**

[Here is a sample code snippet](https://dotnetfiddle.net/5iIN8E).

Thank you for the great library!

Start with the linked .NET Fiddle and trace how the library handles an unspecified verb, a configured default verb, and an invalid verb. Confirm the intended distinction in the issue: an empty verb uses the default, while an invalid verb is reported without parsed output; add or update coverage for these cases if the relevant tests are found.

由索引模型根據 Issue 內容生成。