Render partial from cache substantially faster.

For example we have a view and a partial view named index.html.erb and _todo.html.erb.

/app/views/todos/index.html.erb

Copy<%= render partial: 'todo', collection: @todos, cached: true %>

When cached: true present, Rails will use read_multi to the cache store instead of reading from it every partial.

_/app/views/todos/todo.html.erb

Copy<% cache todo do %>
  <%= todo.name %>
<% end %>