Examples for custom collection dispatchers

[2chanhaeng]

Summary

Recently, Custom Collection Dispatcher was added #310 . This allows users to easily dispatch various Collections of Objects. However, since it was added not long ago, it may still be unfamiliar to users. To solve this problem, writing examples using it will help lower the barrier to entry for users.
This issue suggested by @dahlia in #332 comment

Affected Docs

• Add examples/custom-collection/ and inner files.
• Modify examples/README.md.

What's Missing or Incorrect?

Examples of custom collection dispatcher are needed.

Suggested Content or Structure

• Add examples/custom-collection/ and inner files.
• Modify examples/README.md.

Related Code / Feature

• Issue Custom collection dispatchers #310, PR Support custom collection dispatchers #332
• Custom Collection Dispatchers

[sij411]

Can I work on this? I got curious about custom collections.

[dahlia]

@sij411 Sure, thanks!