Groovy Code to convert Audio file into Bytes

Hi Experts , I have a requirement -

Source system - Request byte -> CPI -> Target System ( FTP folder) - Transmit back audio files in the form of byte to source system .

I am not sure if any of the standard channels can do the conversion . I believe this needs to be handled in CPI for conversion .

Please advice on :

1. Possible groovy code to convert audio file to binary bytes

2.Possible good design if any to handle this situation .

Many thanks in advance to the experts !