code: protected function parseBody($body)
      {
          // Headers come first, then content.
          $isHeader = true;
          $headers = [];
          $content = [];
  
          foreach (explode(static::EOL, $body) as $i => $line) {
  
              if (0 == $i) {
                  // Skip the first line
                  continue;
              }
  
              if ('' == trim($line)) {
                  // First newline starts body in next line.
                  $isHeader = false;
                  continue;
              }
  
              if ($isHeader) {
                  list($header, $value) = explode(':', $line);
                  if ($header) {
                      $headers[strtolower($header)][] = trim($value);
                  }
              } else {
                  $content[] = $line;
              }
          }
  
          return ['headers' => $headers, 'body' => implode(static::EOL, $content)];
      }
docs: Will parse a single [header-]newline-body string.
  
  @param $body
  @return array