I don't understand what it means to "hash". If you get a hash sum all algorithms for calculating checksums allow you to feed the file in small chunks. And methods dependent library files and checksums, which you now enjoy.
jayde.Weber answered on April 19th 20 at 12:38
Go to all packages for working with hashes (e.g. crypto/sha256) are able to receive data in pieces.
Just create an object with the interface io.Writer and there you can use the io.Copy, for example, to redirect the data flow.