@interface _TtCCCC7Message25InProgressMessageDownload26AttachmentDecoderAndWriter7DecoderP33_E488F2EBCE7947B89745EE1E7B527BA212DataConsumer : NSObject <MFDataConsumer> {
    void /* unknown type, empty encoding */ decoder;
}

- (long long)appendData:(id)a0;
- (id)init;
- (void)done;
- (void).cxx_destruct;

@end