LockAndQueue getRegionLock(String encodedRegionName) {
    return getLock(regionLocks, encodedRegionName);
  }
<p>
Locks on namespaces, tables, and regions.
</p>
<p>
Since LockAndQueue implementation is NOT thread-safe, schedLock() guards all calls to these
locks.
</p>
hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/SchemaLocking.java