read (Net::SFTP::Operations::File)

    # File lib/net/sftp/operations/file.rb, line 66
        def read(n=nil)
          loop do
            break if n && @buffer.length >= n
            break unless fill
          end

          if n
            result, @buffer = @buffer[0,n], (@buffer[n..-1] || "")
          else
            result, @buffer = @buffer, ""
          end

          @pos += result.length
          return result
        end