The HTTP form method to use for finding the input for this form. May be 'POST' or 'GET'. Defaults to 'POST'. Note that 'GET' method forms do

public ConfigFormBase::buildForm(array $form, FormStateInterface $for

public &FormStateDecoratorBase::getValues()

public FormStateDecoratorBase::disableRedirect($no_redirect

public FormStateInterface::setResponse(Response $response)

public FormState::setFormState(array $form_state_additions)

public &FormStateDecoratorBase::getCompleteForm()

public FormStateInterface::setGroups(array $groups)

public static FormState::hasAnyErrors() Determines

public FormStateInterface::setErrorByName($name, $message = '')