add serde derive for optional field
@@ -20,6 +20,7 @@ pub struct KickChatMember<'a> {
///Date when the user will be unbanned, unix time. If user is banned for
/// more than 366 days or less than 30 seconds from the current time they
/// are considered to be banned forever
+ #[serde(skip_serializing_if = "Option::is_none")]
pub until_date: Option<u64>,
}
