default CompletableFuture<List<String>> getMasterCoprocessorNames() {
    return getClusterMetrics(EnumSet.of(Option.MASTER_COPROCESSORS))
      .thenApply(ClusterMetrics::getMasterCoprocessorNames);
  }
Returns a list of master coprocessors wrapped by {@link CompletableFuture}
hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncAdmin.java