Description: The applTransactFlowTable contains entries, organized by
application instance or running application element,
direction of flow, and type (request/response) for each
open transaction stream.

The simple model of a transaction used here looks like
this:

    invoker  |   Request     | performer
             | - - - - - - > |
             |               |
             |   Response    |
             | < - - - - - - |
             |               |

Since in some protocols it is possible for an entity
to take on both the invoker and performer roles,
information here is accumulated for transmitted and
received requests, as well as for transmitted and
received responses.  Counts are maintained for both
transactions and bytes transferred.