Merge #380

380: docs: Add readme section about dio r=curquiza a=ahmednfwela

# Pull Request

## Related issue
Fixes #270 
Fixes #356

## What does this PR do?
- Updates readme to include customizing dio

## PR checklist
Please check if your PR fulfills the following requirements:
- [ ] Does this PR fix an existing issue, or have you listed the changes applied in the PR description (and why they are needed)?
- [ ] Have you read the contributing guidelines?
- [ ] Have you made sure that the title is accurate and descriptive of the changes?

Thank you so much for contributing to Meilisearch!


Co-authored-by: Ahmed Fwela <ahmednfwela@bdaya-dev.com>

README.md

@@ -28,12 +28,15 @@
 
 **Meilisearch** is an open-source search engine. [Learn more about Meilisearch.](https://github.com/meilisearch/meilisearch)
 
-## Table of Contents <!-- omit in TOC -->
+## Table of Contents <!-- omit from toc -->
 
 - [📖 Documentation](#-documentation)
 - [⚡ Supercharge your Meilisearch experience](#-supercharge-your-meilisearch-experience)
 - [🔧 Installation](#-installation)
 - [🚀 Getting started](#-getting-started)
+- [Advanced Configuration](#advanced-configuration)
+  - [Customizing the dio instance](#customizing-the-dio-instance)
+  - [Using MeiliDocumentContainer](#using-meilidocumentcontainer)
 - [🤖 Compatibility with Meilisearch](#-compatibility-with-meilisearch)
 - [💡 Learn more](#-learn-more)
 - [⚙️ Contributing](#️-contributing)
@@ -198,6 +201,25 @@ await index.search('wonder', filter: ['id > 1 AND genres = Action']);
 }
 ```
 
+## Advanced Configuration
+
+### Customizing the dio instance
+
+Meilisearch uses [dio](https://pub.dev/packages/dio) internally to send requests, you can provide it with your own interceptors or adapter using the `MeiliSearchClient.withCustomDio` constructor.
+
+### Using MeiliDocumentContainer
+
+The `MeiliDocumentContainer<T>` class contains meilisearch-specific fields (e.g. `rankingScoreDetails`, `_formatted`, `matchesPosition`, etc...).
+
+We define the `mapToContainer()` extension to help you quickly opt-in to this class, example:
+
+```dart
+final res = await index 
+      .search("hello world") 
+      .asSearchResult() //or .asPaginatedResult() if using page parameters
+      .mapToContainer(); 
+```
+
 ## 🤖 Compatibility with Meilisearch
 
 This package guarantees compatibility with [version v1.x of Meilisearch](https://github.com/meilisearch/meilisearch/releases/tag/latest), but some features may not be present. Please check the [issues](https://github.com/meilisearch/meilisearch-dart/issues?q=is%3Aissue+is%3Aopen+label%3A%22good+first+issue%22+label%3Aenhancement) for more info.