isInputMessageContent

isInputMessageContent!InputMessageContent.expect!true;
isInputMessageContent!InputTextMessageContent.expect!true;
isInputMessageContent!InputVenueMessageContent.expect!true;
isInputMessageContent!InputContactMessageContent.expect!true;
isInputMessageContent!string.expect!false;
isInputMessageContent!int.expect!false;
isInputMessageContent!bool.expect!false;