>…egoire/dev/labs/serverless/monolog(appli +) composer require symfony/var-dumper --dev
Restricting packages listed in "symfony/symfony" to "4.3.*"
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Restricting packages listed in "symfony/symfony" to "4.3.*"
Package operations: 1 install, 0 updates, 0 removals
  - Installing symfony/var-dumper (v4.3.4): Loading from cache
Writing lock file
Generating autoload files
ocramius/package-versions: Generating version class...
ocramius/package-versions: ...done generating version class
Executing script cache:clear [OK]
Executing script assets:install public [OK]

>…egoire/dev/labs/serverless/monolog(appli *+) rm -rf var/cache/*
>…egoire/dev/labs/serverless/monolog(appli *+) php bin/console server:dump

                                                                                                                                                                     
  Command "server:dump" is not defined.                                                                                                                              
                                                                                                                                                                     
  Did you mean one of these?                                                                                                                                         
      config:dump-reference                                                                                                                                          
      server:log                                                                                                                                                     
      server:run                                                                                                                                                     
      server:start                                                                                                                                                   
      server:status                                                                                                                                                  
      server:stop                                                                                                                                                    
                                                                                                                                                                     
  You may be looking for a command provided by the "VarDumper Component" which is currently not installed. Try running "composer require symfony/var-dumper --dev".