[alco]

You can panic inside Write() and recover at the top of the DumpBinary() function. This has been demonstrated by Rob Pike and Andrew Gerrand in a talk at Google IO.

As long as you don't leak panics outside of your package, it's OK to use them for non-local error returns.

[Someone]

Yes, but that would work best if the culture was to panic to signal errors. If it is not (as IIRC in go), you need to wrap common library calls to do so.