sub new {
    my $class = shift;

    my %parent_parms = (
        agent       => "WWW-Mechanize/$VERSION",
        cookie_jar  => {},
    );

    my %mech_parms = (
        autocheck   => 0,
        onwarn      => \&WWW::Mechanize::_warn,
        onerror     => \&WWW::Mechanize::_die,
        quiet       => 0,
        stack_depth => 0,
        headers     => {},
    );

    my %passed_parms = @_;

    # Keep the mech-specific parms before creating the object.
    while ( my($key,$value) = each %passed_parms ) {
        if ( exists $mech_parms{$key} ) {
            $mech_parms{$key} = $value;
        }
        else {
            $parent_parms{$key} = $value;
        }
    }

    my $self = $class->SUPER::new( %parent_parms );
    bless $self, $class;

    # Use the mech parms now that we have a mech object.
    for my $parm ( keys %mech_parms ) {
        $self->{$parm} = $mech_parms{$parm};
    }
    $self->{page_stack} = [];
    $self->env_proxy();

    # libwww-perl 5.800 (and before, I assume) has a problem where
    # $ua->{proxy} can be undef and clone() doesn't handle it.
    $self->{proxy} = {} unless defined $self->{proxy};
    push( @{$self->requests_redirectable}, 'POST' );

    $self->_reset_page;

    return $self;
}