* Returns: {Object}

* `execArgv` {string\[]} List of string arguments passed to the Node.js

executable. **Default:** `process.execArgv`.

* `exec` {string} File path to worker file. **Default:** `process.argv[1]`.

* `args` {string\[]} String arguments passed to worker.

**Default:** `process.argv.slice(2)`.

* `cwd` {string} Current working directory of the worker process. **Default:**

`undefined` (inherits from parent process).

* `serialization` {string} Specify the kind of serialization used for sending

messages between processes. Possible values are `'json'` and `'advanced'`.

See [Advanced serialization for `child_process`][] for more details.

**Default:** `false`.

* `schedulingPolicy` {string} Scheduling policy to use between processes.

**Default:** `cluster.SCHED_RR`. See \[`cluster.schedulingPolicy`]\[] for

details.

* `silent` {boolean} Whether or not to send output to parent's stdio.

**Default:** `false`.

* `stdio` {Array} Configures the stdio of forked processes. Because the

cluster module relies on IPC to function, this configuration must contain an

`'ipc'` entry. When this option is provided, it overrides `silent`. See

[`child_process.spawn()`][]'s [`stdio`][].

* `uid` {number} Sets the user identity of the process. (See setuid(2).)

* `gid` {number} Sets the group identity of the process. (See setgid(2).)

* `inspectPort` {number|Function} Sets inspector port of worker.

This can be a number, or a function that takes no arguments and returns a

number. By default each worker gets its own port, incremented from the

primary's `process.debugPort`.

* `windowsHide` {boolean} Hide the forked processes console window that would

normally be created on Windows systems. **Default:** `false`.

After calling [`.setupPrimary()`][] (or [`.fork()`][]) this function will return

the cluster settings, including the default values.