It takes from 5 (shortest) to almost 40 (longest) minutes for `bitcoin-cli gettxoutsetinfo` to return an _empty_ dict. I noticed this first whilst configuring the Statoshi branch of Bitcoin Core, but went back to install Bitcoin Core (git clone -b v0.11.2 https://github.com/bitcoin/bitcoin.git) to find the same results.

```
20:10 pi@raspinode:~/bin/bitcoin.orig $ bitcoin-cli gettxoutsetinfo
{
}
20:12 pi@raspinode:~/bin/bitcoin.orig $ bitcoin-cli getinfo
{
    "version" : 110200,
    "protocolversion" : 70002,
    "blocks" : 393193,
    "timeoffset" : 0,
    "connections" : 12,
    "proxy" : "",
    "difficulty" : 113354299801.47113037,
    "testnet" : false,
    "relayfee" : 0.00005000,
    "errors" : ""
}
20:17 pi@raspinode:~/bin/bitcoin.orig $
```

Raspberry Pi 2 - 1GB memory - 4 core CPU 900MHz - Blockchain on SanDisk Ultra Android microSDXC 128GB up to 80 MB/Sec Class 10

All other RPC calls through bitcoin-cli are answered promptly and correctly.
See also issue on jlopp/statoshi https://github.com/jlopp/statoshi/issues/19#issuecomment-171350739

{
    UniValue rv(UniValue::VOBJ);
    rv.push_back(Pair("id", name));
    rv.push_back(Pair("version", version));
    rv.push_back(Pair("reject", SoftForkMajorityDesc(version, pindex, consensusParams)));
    return rv;
}
static UniValue BIP9SoftForkDesc(const Consensus::Params& consensusParams, Consensus::DeploymentPos id)
{
    UniValue rv(UniValue::VOBJ);
    const ThresholdState thresholdState = VersionBitsTipState(consensusParams, id);
    switch (thresholdState) {
    case THRESHOLD_DEFINED: rv.push_back(Pair("status", "defined")); break;
    case THRESHOLD_STARTED: rv.push_back(Pair("status", "started")); break;
    case THRESHOLD_LOCKED_IN: rv.push_back(Pair("status", "locked_in")); break;
    case THRESHOLD_ACTIVE: rv.push_back(Pair("status", "active")); break;
    case THRESHOLD_FAILED: rv.push_back(Pair("status", "failed")); break;
    }
    if (THRESHOLD_STARTED == thresholdState)
    {
        rv.push_back(Pair("bit", consensusParams.vDeployments[id].bit));
    }
    rv.push_back(Pair("startTime", consensusParams.vDeployments[id].nStartTime));
    rv.push_back(Pair("timeout", consensusParams.vDeployments[id].nTimeout));
    return rv;
}
void BIP9SoftForkDescPushBack(UniValue& bip9_softforks, const std::string &name, const Consensus::Params& consensusParams, Consensus::DeploymentPos id)