public boolean waitTableSharedLock(final Procedure<?> procedure, final TableName table) {
    return waitTableQueueSharedLock(procedure, table) == null;
  }
Suspend the procedure if the specified table is already locked. other "read" operations in the
table-queue may be executed concurrently,
@param procedure the procedure trying to acquire the lock
@param table     Table to lock
@return true if the procedure has to wait for the table to be available
hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/MasterProcedureScheduler.java