class Middleman::SourceWatcher

def to_s

if the object is huge or has cyclic references, like this.
messages, which can take a long time (minutes at full CPU)
where Ruby will call to_s/inspect while printing exception
Work around this bug: http://bugs.ruby-lang.org/issues/4521 
def to_s
  "#<Middleman::SourceWatcher:0x#{object_id} type=#{@type.inspect} directory=#{@directory.inspect}>"
end