code: public N1qlParams withCredentials(String login, String password) {
          credentials.put(login, password);
          return this;
      }
docs: Allows to add a credential username/password pair to this request. If a credential for that
  username was previously set by a similar call, it is replaced.
  
  @param login the username/bucketname to add a credential for.
  @param password the associated password.
  @return this {@link N1qlParams} for chaining.