fix encoding error when piping stdout to file

[zhuoqyin]

The new code changes would raise UnicodeDecodeError on some terminals when you redirect the output to file.

See this stackoverflow for detailed explanation.

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[zhuoqyin]

I signed it!

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CLAs look good, thanks!

[oahziur]

Hi @zhuoqyin ,

I think this bug has been fixed in the master branch, can you check if you still get the UnicodeDecodeError in your terminal with the current head? Thanks!