This reverts commit 3420a145, reversing
changes made to afb66a5a.

Plus a couple of related ActionPack patches.

Implement naive partial caching mechanism.

Add test for LogSubscriber

Use ActionView::Base#log_payload to store log_subscriber's payload, so we can pass cache result into it.

Fixed tests

Remove useless settings

Check if #log_payload exists before calling it. Because other classes also includes CacheHelper but don't have is attribute

Use @log_payload_for_partial_reder instead of #log_payload to carry ActionView's payload.

Update test's hash syntax

Add configuration to enable/disable fragment caching logging

Remove unless test and add new test to ensure cache info won't effect next rendering's log

Move :enable_fragment_cache_logging config from ActionView to ActionPack

Apply new config to tests

Update actionview's changelog

Update configuration guide

Improve actionview's changelog

Refactor PartialRenderer#render and log tests

Mute subscriber's log instead of disabling instrumentation.

Fix typo, remove useless comment and use new hash syntax

Improve actionpack's log_subscriber test

Fix rebase mistake

Apply new config to all caching intstrument actions

The current code base is not uniform. After some discussion,
we have chosen to go with double quotes by default.

We don't need to instrument another event as
`ActiveSupport::LogSubscriber` already tracks when the instrumentation
starts.

Close #23717

Added log "Rendering ...", when starting to render a template, to log that we have started to render something, at the very beginning.
This helps to easily identify queries from controller vs views

Fixes #23710

Augments the collection caching with some instrumentation that's logged.

For collections that have been cached like:

```ruby
<%= render partial: 'notifications/notification', collection: @notifications, cached: true %>
```

We'll output a line showing how many cache hits we had when rendering it:

```
  Rendered collection of notifications/_notification.html.erb [0 / 100 cache hits] (3396.5ms)
```

The Logger by default includes a guard which checks for the
logging level. By removing the custom logging guards, we can decouple
the logging guard from the logging action to be done.

This also follows the good practice listed on http://guides.rubyonrails.org/debugging_rails_applications.html#impact-of-logs-on-performance.

Revert "drop one more string allocation"

This reverts commit 4d15661d.

make the logs a little simpler to view, put the render message inline with other events, pull processing to char[0] and add a new line to the completed. looks more like a block now, which is useful for serial actions like test/dev

Signed-off-by: NJosé Valim <jose.valim@gmail.com>

Move Rails::LogSubscriber to ActiveSupport::LogSubscriber, allowing frameworks like ActiveRecord and ActiveResource to log outsude Rails::Application [#4816 state:resolved]