confusing variable name fix

[freax]

It's pretty confusing to use the same variable name that function parameter (especially you have different highlight for parameter variables in your IDE).
This PR makes write-function more readable.

[mwillbanks]

I understand why you are stating that, however, you are actually now creating a copy that will yield another variable that needs to be cleaned up by the garbage collector. However, I actually find this less readable but it is subjective to whomever might be viewing it. Leveraging the same variable name is often a practice of conserving memory. Imagine my session data contained very large data (it's not common but I see it happen in practice). Overall, I do not believe that this is a useful change at this point in time.