Custom parallel thread job example

IJobParallel.cs

[JobProducerType(typeof(JobCustomParallelExtensions.JobCustomParallelStruct<>))]
public interface IJobCustomParallel
{
    void Execute();
}

public static class JobCustomParallelExtensions
{
     public static void EarlyJobInit<T>() where T : struct, IJobCustomParallel
     {
         JobCustomParallelStruct<T>.Initialize();
     }

     private static IntPtr GetReflectionData<T>() where T : struct, IJobCustomParallel
     {
         JobCustomParallelStruct<T>.Initialize();
         return JobCustomParallelStruct<T>.jobReflectionData.Data;
     }

     public static unsafe JobHandle Schedule<TJob>(this TJob jobData, JobHandle dependsOn = default)
         where TJob : struct, IJobCustomParallel
     {
         var fullData = new JobCustomParallelStruct<TJob>
         {
             JobData = jobData
         };

         var scheduleParams = new JobsUtility.JobScheduleParameters(UnsafeUtility.AddressOf(ref fullData),
             GetReflectionData<TJob>(), dependsOn, ScheduleMode.Parallel);

         return JobsUtility.ScheduleParallelFor(ref scheduleParams, 100, 10);
     }

     public static unsafe JobHandle ScheduleByRef<TJob>(this ref TJob jobData, JobHandle dependsOn = default)
         where TJob : struct, IJobCustomParallel
     {
         var fullData = new JobCustomParallelStruct<TJob>
         {
             JobData = jobData
         };

         var scheduleParams = new JobsUtility.JobScheduleParameters(UnsafeUtility.AddressOf(ref fullData),
             GetReflectionData<TJob>(), dependsOn, ScheduleMode.Parallel);

         return JobsUtility.ScheduleParallelFor(ref scheduleParams, 100, 10);
     }

     [StructLayout(LayoutKind.Sequential)]
     internal struct JobCustomParallelStruct<TJob>
         where TJob : struct, IJobCustomParallel
     {
         public TJob JobData;

         internal static readonly SharedStatic<IntPtr> jobReflectionData =
             SharedStatic<IntPtr>.GetOrCreate<JobCustomParallelStruct<TJob>>();

         [BurstDiscard]
         internal static void Initialize()
         {
             if (jobReflectionData.Data == IntPtr.Zero)
             {
                 jobReflectionData.Data = JobsUtility.CreateJobReflectionData(typeof(JobCustomParallelStruct<TJob>),
                     typeof(TJob), (ExecuteJobFunction)Execute);
             }
         }

         private delegate void ExecuteJobFunction(ref JobCustomParallelStruct<TJob> fullData, IntPtr additionalPtr,
             IntPtr bufferRangePatchData,
             ref JobRanges ranges, int jobIndex);

         public static void Execute(ref JobCustomParallelStruct<TJob> fullData, IntPtr additionalPtr, IntPtr bufferRangePatchData,
             ref JobRanges ranges, int jobIndex)
         {
             while (true)
             {
                 if (!JobsUtility.GetWorkStealingRange(ref ranges, jobIndex, out var begin, out var end))
                     return;
                    
                 for (var i = begin; i < end; i++)
                 {
                     fullData.JobData.Execute();
                 }
             }
         }
     }
}