my $res = $ua->post( $url, $field_name => $value, Content => $content );

##</code><code>##

$ua->post(
    $self->{'auth'}->api_url_base . 'shares',
    Content => encode_json($json),
    $header,
    );

##</code><code>##

$ua->post(
    $self->{'auth'}->api_url_base . 'shares',
    %$header,
    Content => encode_json($json)
);