Listen creates a listener which returns new connections whenever someone connects
to a socat or mock driver proxy instance running inside the given pod.
socat must by started with "<listen>,fork TCP-LISTEN:<port>,reuseport"
for this to work. "<listen>" can be anything that accepts connections,
for example "UNIX-LISTEN:/csi/csi.sock". In this mode, socat will
accept exactly one connection on the given port for each connection
that socat itself accepted.
Listening stops when the context is done or Close() is called.