None of the above solutions work for very long strings in golang. I needed data near the end of a ~60k character string buffer, in library code (so I couldn't just add a print statement).

The solution I found was to use slice notation, in the Debug Console:

string(buf[:60000])

This shows the exact contents of the buffer, without truncation, up to the slice index. So if you use a big enough index, you can display an arbitrarily large string.