• [ BREAKING CHANGE (BARELY) ]
  Log::Fmt now includes a formal specification of the logfmt grammar we
  implement, as well as a description of algorithmns to correctly
  encode strings. The code has been updated to fall in line, meaning:
  
• tabs now become \t
  
• control and vertical space characters are now encoded as \x{...} of
  their UTF-8-encoded form, not their Unicode codepoint value
  
• the "\" character now triggers double-quoting