static boolean isGood(RegionLocations locs, int replicaId) {
    if (locs == null) {
      return false;
    }
    HRegionLocation loc = locs.getRegionLocation(replicaId);
    return loc != null && loc.getServerName() != null;
  }
Create a new {@link RegionLocations} based on the given {@code oldLocs}, and remove the
location for the given {@code replicaId}.
<p/>
All the {@link RegionLocations} in async locator related class are immutable because we want to
access them concurrently, so here we need to create a new one, instead of calling
{@link RegionLocations#remove(int)}.
hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncRegionLocatorHelper.java