class FDB::Future

def callback_wrapper(f, &block)
  begin
    yield f
  rescue Exception
    begin
      $stderr.puts "Discarding uncaught exception from user callback:"
      $stderr.puts "#{$@.first}: #{$!.message} (#{$!.class})", $@.drop(1).map{|s| "\t#{s}"}
    rescue Exception
    end
  end
end