[9.x] Add mail/notification tags & metadata docs

[kbond]

Ref: laravel/framework#40783

[taylorotwell]

I feel like it would be good to flesh out a bit what these actually do. Once I tag something, then what? How does it help me on my email provider?

[kbond]

Perhaps something similar to when we have in the Symfony docs:

"Certain 3rd party transports support email tags and metadata, which can be used for grouping, tracking and workflows. You can add these to your Mailable. If your transport supports metadata/tags, they will be converted to their appropriate format."

Maybe with links to different drivers docs on the feature?

• Postmark: tags/metadata.
• Mailgun: tags/metadata
• SES: metadata *tags not supported (not available until symfony/amazon-mailer:6.1+) [9.x] Implement email "metadata" for SesTransport framework#41422

[taylorotwell]

@kbond and, to clarify, what SES refers to as "tags" in their documentation you would actually use the "metadata" Laravel method for... and it is available next Tuesday on our release day since your PR was just merged?

[kbond]

what SES refers to as "tags" in their documentation you would actually use the "metadata" Laravel method for

Correct as their "tags" have a key and a value. Our "tags" just have a value.

and it is available next Tuesday on our release day since your PR was just merged?

Yes, all the drivers Laravel has documented support both tags and metadata with the exception of SES, which just supports metadata.

can you point me to where "tags" and "metadata" are clearly defined from Symfony mailer's perspective? What is the purpose of a tag and what is the purpose of metadata? It feels like it would be great to have documentation on what each type (tag / metadata) does for each driver. (laravel/framework#41422 (comment))

Does my above comment provide this?

[taylorotwell]

@kbond yeah I think we're good. I'll take it from here - thanks!