Support for Signature widgets/annotations ?

[dickverweij]

Is your feature request related to a problem? Please describe. We use your fabulous package to show pdf's in our flutter app. We noticed that the signature widgets/annotations are not shown.

Describe the solution you'd like support for signature widgets/annotation in the rendering https://www.adobe.com/devnet-docs/acrobatetk/tools/DigSig/Acrobat_DigitalSignatures_in_PDF.pdf

Describe alternatives you've considered There are no alternatives

Additional context