RegionCoprocessorHost host = new RegionCoprocessorHost(r, null, conf);
r.setCoprocessorHost(host);
for (Class<?> implClass : implClasses) {
host.load(implClass, Coprocessor.PRIORITY_USER, conf);
Coprocessor c = host.findCoprocessor(implClass.getName());
assertNotNull(c);
}
// Here we have to call pre and postOpen explicitly.
host.preOpen();