long lived uplinks could just hold on to connections forever
if their client to the storagenode or satellite isn't closed.
this will prevent that from happening on the client. more
changes will be necessary to add appropriate prevention on
the servers.
Change-Id: Ib36d85e70cbafb315664ad7657bb70b936b3828c
keep a pool of connections open when dialing for drpc. this
makes it so that long lived clients (like lib/uplink's Project)
don't continue to use a bad connection forever. it also allows
for concurrent rpcs.
Change-Id: If649b286050e4f09c413fadc3e1ce88f5fc6e600