Add option to send nonblocking chat messages

types.go

@@ -114,6 +114,7 @@ type SendMessageOptions struct {
 	ReplyTo           *chat1.MessageID   `json:"reply_to,omitempty"`
 	ExplodingLifetime *ExplodingLifetime `json:"exploding_lifetime,omitempty"`
 	UnreadOnly        bool               `json:"unread_only,omitempty"`
+	NonBlock          bool               `json:"nonblock,omitempty"`
 }
 
 type sendMessageParams struct {