Function QuorumTracker.expand
attempts to expand quorum at node id
expansion here means adding id to the known quorum
and add its dependencies as defined by qset
returns true if expansion succeeded
id was unknown
id was known and didn't have a quorumset
returns false on failure
if expand fails, the caller should instead use rebuild
extern(C++) bool expand
(
ref const(ulong) id,
shared_ptr!(scpd.types.Stellar_SCP.SCPQuorumSet) qSet
);