code: private function _relativeSymlinkWithFallback(string $originDir, string $targetDir): string
      {
          try {
              $this->_symlink($originDir, $targetDir, true);
              $method = AssetsInstallCommand::METHOD_RELATIVE_SYMLINK;
          }
          catch (IOException $e) {
              $method = $this->_absoluteSymlinkWithFallback($originDir, $targetDir);
          }
  
          return $method;
      }
docs: Try to create relative symlink.
  Falling back to absolute symlink and finally hard copy.
  
  @param string $originDir
  @param string $targetDir
  
  @return string