docs: public static synchronized RpcManager instance(final TSDB tsdb) {
      final RpcManager existing = INSTANCE.get();
      if (existing != null) {
        return existing;
      }
  
      final RpcManager manager = new RpcManager(tsdb);
      
      // Load any plugins that are enabled via Config.  Fail if any plugin cannot be loaded.
  
      final ImmutableList.Builder<RpcPlugin> rpcBuilder = ImmutableList.builder();
      if (tsdb.getConfig().hasProperty("tsd.rpc.plugins")) {
        final String[] plugins = tsdb.getConfig().getString("tsd.rpc.plugins").split(",");
        manager.initializeRpcPlugins(plugins, rpcBuilder);
      }
      manager.rpc_plugins = rpcBuilder.build();
  
      final ImmutableMap.Builder<String, TelnetRpc> telnetBuilder = ImmutableMap.builder();
      final ImmutableMap.Builder<String, HttpRpc> httpBuilder = ImmutableMap.builder();
      manager.initializeBuiltinRpcs(tsdb.getMode(), telnetBuilder, httpBuilder);
      manager.telnet_commands = telnetBuilder.build();
      manager.http_commands = httpBuilder.build();
  
      final ImmutableMap.Builder<String, HttpRpcPlugin> httpPluginsBuilder = ImmutableMap.builder();
      if (tsdb.getConfig().hasProperty("tsd.http.rpc.plugins")) {
        final String[] plugins = tsdb.getConfig().getString("tsd.http.rpc.plugins").split(",");
        manager.initializeHttpRpcPlugins(tsdb.getMode(), plugins, httpPluginsBuilder);
      }
      manager.http_plugin_commands = httpPluginsBuilder.build();
  
      INSTANCE.set(manager);
      return manager;
    }