Binary: Put -> Builder

[Don Stewart]

haskell:
> Don Stewart wrote:
>> OK. I'm preparing the 0.5 release of binary atm, so will expose these.
>>
>> -- Don
>
> Don: I had proposed (with a patch) to let the caller of runPut give a 
> size hint so the first chunk allocated for the Lazy ByteString would not 
> have to always be the default value (which I remember being about 32 kilo 
> bytes).  If the first allocation filled up the subsequent chunks are 
> still the default size.
>
> My use case was for the protocol-buffers package where the serialized 
> message sizes are both known in advance and often much much smaller than 
> this.  I have no benchmarks, but it feels wrong to have my library 
> constantly over-allocating.
>
> Is such a feature going to be accepted into the binary package?  If not 
> then I may just copy over and patch the Put monad.  (I do not use an 
> external Get monad, the protocol-buffers package includes its own Get 
> monad).

Could you dig up the patch again?