public static NativeArray <ArrayType> GetSingletonBufferArray
        <BufferType, ArrayType>(this SystemBase s)
            where BufferType : unmanaged, IBufferElementData
            where ArrayType : unmanaged
        {
            var e = s.GetSingletonEntity <BufferType>();

            return(s.GetBufferArray <BufferType, ArrayType>(e));
        }