Registers a new interval that will execute once in the current or the next step, depending on when it is registered. If an immediate is registered while immediates are processing, it will be executed in the next step. However, if an interval is registered by a timeout or interval callback, the immediate _will_ process in the same step in which it was registered. `...` are the arguments passed to the `callback` function that is called when the immediate executes. `setImmediate` returns an unique numeric immediate ID that can be passed to `clearImmediate`. If `callback` is not a function, an error is raised when the immediate is executed.
#### `clearImmediate(id)`
Registers a new interval that will execute once in the current or the next step, depending on when it is registered. If an immediate is registered while immediates are processing, it will be executed in the next step. However, if an interval is registered by a timeout or interval callback, the immediate _will_ process in the same step in which it was registered. `...` are the arguments passed to the `callback` function that is called when the immediate executes. `setImmediate` returns an unique numeric immediate ID that can be passed to `clearImmediate`. If `callback` is not a function, an error is raised when the immediate is executed.
#### `clearImmediate(id)`