Add capability to Connect:Direct to work around undesirable DVIPA behavior

We'd like to request a new initialization parm for Connect:DIrect (CD) to disable outbound TCP connection establishment until after the DTF opens its TCP listener ports.

Our DTFs both send traffic and listen for traffic. We have had situations where outbound connections effectively grab the DVIPA at DTF startup then release it when done, releasing it for all connections including the DTF listener. The subsequent disruption to TCP connections is undesirable to put it mildly.

As you can see from the related support case the recommended solution from support is to use MODDVIPA since they state that it's a TCP issue, not a CD issue. One of the problems with this is that MODDVIPA does not work if coded in JCL and the DTF is cancelled, so this is not a viable solution. The other way to invoke MODDVIPA at startup and shutdown consistently is to code more automation, adding more complexity especially when moving DTFs between systems (for maintenance windows, performance, DR exercises, etc).

In the related support case L3 offered only MODDVIPA as the solution. After carefully reviewing their response it seems as though they might have been making assumptions about our usage of DVIPA that are not correct. Our DTF is the only user of the DVIPAs, so no chance of some other address space hijacking the DTF DVIPAs.

Given the way that we (and likely most other customers) use CD with DVIPAs and the trouble of moving to MODDVIPA, we're asking that you review this RFE and provide an init parm to ensure that the CD DTF listener grabs the DVIPA before any CD outbound processes grab them.