Custom Flat File Disassembler behaviour

Hello,
    We have a custom dissassembler pipeline component for disassembling a flat file.
   
    Actually, before Disassembly,there is another pipeline component that does some custom processing.

    There is a send port that “passthrutransmits” the disassembled messages onto a output folder.The send port subscribes to the Receive port.

    When we pass a large flat file,with thousands of records in it(each record will be dissassembled into
    a xml message), it takes around 12 minutes for the entire pipeline to complete.

    Now we see that only after that pipeline completes in entirety (i.e. after 12 minutes) does the first files
    start appearing in the output folder.

    I was thinking the custom flatfile dissassembler component operates in a “streaming”  mode i.e. it dissassembles
    a message and posts it to the MessageBox.So the files should start appearing in the out put folder much much
    earlier.        
     
    Is my understanding correct? if yes, any ideas what is going wrong?

Regards,
anon