code: function getAction(key) {
      const keyString = key.toString();
  
      if (keyString.match(/CERTIFICATE\sREQUEST-{5}$/m)) {
          return 'req';
      }
      else if (keyString.match(/(PUBLIC|PRIVATE)\sKEY-{5}$/m)) {
          return 'rsa';
      }
  
      return 'x509';
  }
docs: Get OpenSSL action from buffer
  
  @private
  @param {buffer} key Private key, certificate or CSR
  @returns {string} OpenSSL action