public FormState::setMethod($method)
Sets the HTTP method to use for the form's submission.
This is what the form's "method" attribute should be, not necessarily what the current request's HTTP method is. For example, a form can have a method attribute of POST, but the request that initially builds it uses GET.
Parameters
string $method: Either "GET" or "POST". Other HTTP methods are not valid form submission methods.
Return value
$this
Overrides FormStateInterface::setMethod
See also
\Drupa