Uses struct/interface embedding with the embedded structs/interfaces being empty for oss. Also methods on the server/client types are defaulted to do nothing for OSS
* Adds client-side retry for no leader errors.
This paves over the case where the client was connected to the leader
when it loses leadership.
* Adds a configurable server RPC drain time and a fail-fast path for RPCs.
When a server leaves it gets removed from the Raft configuration, so it will
never know who the new leader server ends up being. Without this we'd be
doomed to wait out the RPC hold timeout and then fail. This makes things fail
a little quicker while a sever is draining, and since we added a client retry
AND since the server doing this has already shut down and left the Serf LAN,
clients should retry against some other server.
* Makes the RPC hold timeout configurable.
* Reorders struct members.
* Sets the RPC hold timeout default for test servers.
* Bumps the leave drain time up to 5 seconds.
* Robustifies retries with a simpler client-side RPC hold.
* Reverts untended delete.
* Changes default Raft protocol to 3.
* Changes numPeers() to report only voters.
This should have been there before, but it's more obvious that this
is incorrect now that we default the Raft protocol to 3, which puts
new servers in a read-only state while Autopilot waits for them to
become healthy.
* Fixes TestLeader_RollRaftServer.
* Fixes TestOperator_RaftRemovePeerByAddress.
* Fixes TestServer_*.
Relaxed the check for a given number of voter peers and instead do
a thorough check that all servers see each other in their Raft
configurations.
* Fixes TestACL_*.
These now just check for Raft replication to be set up, and don't
care about the number of voter peers.
* Fixes TestOperator_Raft_ListPeers.
* Fixes TestAutopilot_CleanupDeadServerPeriodic.
* Fixes TestCatalog_ListNodes_ConsistentRead_Fail.
* Fixes TestLeader_ChangeServerID and adjusts the conn pool to throw away
sockets when it sees io.EOF.
* Changes version to 1.0.0 in the options doc.
* Makes metrics test more deterministic with autopilot metrics possible.
