The Go Race Detector pointed out a data race between
the methods ChangeMax64 and State or GetMax64.
State already takes the lock, but others did not.

Display elapsed time at the end of the bar when elapsedTime is enabled
while predictTime is set to false.

Demo:
```
70% |███████   |  [0s]
```

…ent-bytes

Finish() should update state.currentBytes

fix race condition when changing max

fix: make elapsedTime option work in non-spinner mode