code: public function getDefinition()
      {
          return new FixerDefinition(
              'Add leading `\` before function invocation to speed up resolving.',
              [
                  new CodeSample(
                      '<?php
  
  function baz($options)
  {
      if (!array_key_exists("foo", $options)) {
          throw new \InvalidArgumentException();
      }
  
      return json_encode($options);
  }
  '
                  ),
                  new CodeSample(
                      '<?php
  
  function baz($options)
  {
      if (!array_key_exists("foo", $options)) {
          throw new \InvalidArgumentException();
      }
  
      return json_encode($options);
  }
  ',
                      [
                          'exclude' => [
                              'json_encode',
                          ],
                      ]
                  ),
                  new CodeSample(
                      '<?php
  namespace space1 {
      echo count([1]);
  }
  namespace {
      echo count([1]);
  }
  ',
                      ['scope' => 'all']
                  ),
                  new CodeSample(
                      '<?php
  namespace space1 {
      echo count([1]);
  }
  namespace {
      echo count([1]);
  }
  ',
                      ['scope' => 'namespaced']
                  ),
                  new CodeSample(
                      '<?php
  myGlobalFunction();
  count();
  ',
                      ['include' => ['myGlobalFunction']]
                  ),
                  new CodeSample(
                      '<?php
  myGlobalFunction();
  count();
  ',
                      ['include' => ['@all']]
                  ),
                  new CodeSample(
                      '<?php
  myGlobalFunction();
  count();
  ',
                      ['include' => ['@internal']]
                  ),
                  new CodeSample(
                      '<?php
  $a .= str_repeat($a, 4);
  $c = get_class($d);
  ',
                      ['include' => ['@compiler_optimized']]
                  ),
              ],
              null,
              'Risky when any of the functions are overridden.'
          );
      }
docs: {@inheritdoc}