withContentOrNull

inline fun <T : MessageContent> ContentMessage<*>.withContentOrNull(): ContentMessage<T>?
inline fun <T : MessageContent> CommonMessage<*>.withContentOrNull(): CommonMessage<T>?
inline fun <T : MessageContent> ChannelContentMessage<*>.withContentOrNull(): ChannelContentMessage<T>?
inline fun <T : MessageContent> PrivateContentMessage<*>.withContentOrNull(): PrivateContentMessage<T>?
inline fun <T : MessageContent> PublicContentMessage<*>.withContentOrNull(): PublicContentMessage<T>?
inline fun <T : MessageContent> GroupContentMessage<*>.withContentOrNull(): GroupContentMessage<T>?
inline fun <T : MediaGroupContent> MediaGroupMessage<*>.withContentOrNull(): MediaGroupMessage<T>?