Control characters cause log lines to not be sent as separate events

[nhibberd]

Completed 108 of 118 part(s) with 10 file(s) remaining
2017-01-27 02:40:40download: s3://... to ..

[charleso]

Some more information.

fsPut :: FileSyncer -> ByteString -> IO () is basically assuming that each ByteString ends in \n. This is mostly true given how it's consumed at the moment by handles that buffer, but not guaranteed.

Suggested fix:

1. Expose a Conduit function that:

• Replaces the relevant \r and other control characters to \n
• Call lines

2. Deprecate fsPut and add fsPutLn which appends a \n