README.md in tracer_client-0.2.1 vs README.md in tracer_client-0.3.0

@@ -44,9 +44,19 @@
 rescue => e
     Log.exception(e, 'Unable to send request', 'request', request_data: data)
 end
 ```
 
+To cancel sending log messages in production mode you should use the environment variable NO_TRACER with a truthy value (true, TRUE, 1, etc).
+```ruby
+ENV['NO_TRACER'] - true
+```
+
+In a development mode sending messages is disabled by default. Sending messages can be re-enabled using a TRACER environment variable with a truthy value.
+```ruby
+ENV['TRACER'] - true
+```
+
 ## Development
 
 After checking out the repo, run `bin/setup` to install dependencies. You can also run `bin/console` for an interactive prompt that will allow you to experiment.
 
 To install this gem onto your local machine, run `bundle exec rake install`. To release a new version, update the version number in `version.rb`, and then run `bundle exec rake release`, which will create a git tag for the version, push git commits and tags, and push the `.gem` file to [rubygems.org](https://rubygems.org).