code: def read (filename, as: user, on: hosts, quiet: false)
        log.info "read: #{filename}", quiet: quiet do
          hash_map(hosts) do |host|
            host.read filename, as: as
          end
        end
      end
docs: Reads a remote file from each host.
   @param [String] filename The file to read.
   @return [Hash] A hash of +Host+ objects to +Strings+ of the file contents.
   @macro onable
   @macro asable
   @macro quietable