code: public function read($filePath)
      {
          if ('php://stdin' === $filePath) {
              if (null === $this->stdinContent) {
                  $this->stdinContent = $this->readRaw($filePath);
              }
  
              return $this->stdinContent;
          }
  
          return $this->readRaw($filePath);
      }
docs: @param string $filePath
  
  @return string