@Override
  public void execProcedure(String signature, String instance, Map<String, String> props)
    throws IOException {
    get(admin.execProcedure(signature, instance, props));
  }
The {@link Admin} implementation which is based on an {@link AsyncAdmin}.
hbase-client/src/main/java/org/apache/hadoop/hbase/client/AdminOverAsyncAdmin.java