Multi writer - multi reader fifos

Special kind of fifos where any number of producers and readers may be "connected". This fifos provides the following features:

• Transfers are done in indivisible blocks of contiguous data
• Read/Write? operations are done in packets of one or more blocks
• Blocks may be read/written in between of others, even in one write operation
• Blocks always arrive in order (even if not contiguous because of preceding point)