Pipeline components are an advanced aspect of BizTalk often overlooked or often implemented in a manner that breaks the careful streaming model of BizTalk Server.  Implementing pipeline components in a truly stream based way allows BizTalk to process messages of arbitrary and effectively unlimited size.  This example shows how to use a stream to archive received messages in a way that avoids reading the entire message into memory. 

https://code.msdn.microsoft.com/BizTalk-stream-based-d6ef0f1f