Feat: Enable passing in Extras using Custom Annotations

[farmery]

Summary

This PR adds functionality that allows developers to pass extras with requests using custom classes.

Problem

Imagine you want every request in your app to include some additional metadata, such as an id and a region. Without this feature, you would have to annotate each request manually with something like Extra({'id': '1234', 'region': 'ng'}). While this approach works, it requires passing the key-value pairs each time, which introduces several risks:

Developers may inadvertently misspell a key (e.g., regoin instead of region).
A required key might be forgotten or omitted.
The repeated manual input increases the chance of inconsistency,

Solution

Introduce TypedExtras, which developers can extend to provide extras in a structured and type-safe manner. By defining fields within the custom class, developers can avoid manual key-value entry, ensuring consistency and reducing the risk of errors.

Example:

class MetaData extend TypedExtras {
 final String id;
 final String region;
 const MetaData({required this.id, required region});
}

@MetaData(
  id: '1234',
  region: 'ng',
)
@GET("/get")
Future<String> fetchData();

// Which will generate 
final _extras = <String, dynamic>{
 'id': '1234',
 'region': 'ng',
}

[trevorwang]

Hi @farmery , thanks for the great work.

Lets bump the lib versions and update the change logs before we merge that changes.

[farmery]

Hi @trevorwang I just updated the change logs and versions

[trevorwang]

New version has been deployed @farmery

[moshe5745]

@farmery What a timing!
I came to implement some features in our app by passing headers and deleting them in the interceptor.
Came to the changelog and see this... Thank you very much!

@trevorwang Could you copy-paste the example provided here to the docs?

[moshe5745]

@farmery
Is it possible to use TypedExtras only for typing without the default value?
I mean I have some API endpoint. I want the extras to be typed.
Right now when I extract them in the interceptor I have Map<String, dynamic>. Is it possible to infer the type somehow? Or is it a feature on the Dio side?

[trevorwang]

@farmery What a timing! I came to implement some features in our app by passing headers and deleting them in the interceptor. Came to the changelog and see this... Thank you very much!

@trevorwang Could you copy-paste the example provided here to the docs?

Would you like to submit a PR for this? @moshe5745

[moshe5745]

@farmery What a timing! I came to implement some features in our app by passing headers and deleting them in the interceptor. Came to the changelog and see this... Thank you very much!
@trevorwang Could you copy-paste the example provided here to the docs?

Would you like to submit a PR for this? @moshe5745

Sure