To create a job in Unity you need to implement the IJob interface. IJob allows you to schedule a single job that runs in parallel to any other jobs that are running. 
Note: A “job” is a collective term in Unity for any struct that implements the IJob interface.
To create a job, you need to:
IJob.When executing the job, the Execute method runs once on a single core.
Note: When designing your job, remember that they operate on copies of data, except in the case of NativeContainer. So, the only way to access data from a job in the main thread is by writing to a NativeContainer. 
// Job adding two floating point values together
public struct MyJob : IJob
{
    public float a;
    public float b;
    public NativeArray<float> result;
    public void Execute()
    {
        result[0] = a + b;
    }
}
2018–06–15 Page published with editorial review
C# Job System exposed in 2018.1 NewIn20181