Question about the performance of fused vector operations

Hi,
I have profiled some of my code that is using `Data.Vector.Unboxed` and to my confusion the biggest cost centre is the `(>>=)` on `Identity` from `Data.Vecor.Fusion.Util`.
In fact, it is individually responsible for 18% of my execution time. Together with its children it is responsible for 87% of the time, which is expected because my program is basically only using Vectors. I am not familiar with the stream fusion internals of `Data.Vector`.

Is this performance normal?

One detail about my code: I am mostly using map/fold and I need to store a lot of intermediate result vectors in a datastructure.