class Aws::Plugins::ChecksumAlgorithm::AwsChunkedTrailerDigestIO

def read(length, buf)
  # account for possible leftover bytes at the end, if we have trailer bytes, send them
  if @trailer_io
    return @trailer_io.read(length, buf)
  end
  chunk = @io.read(length)
  if chunk
    @digest.update(chunk)
    application_chunked = "#{chunk.bytesize.to_s(16)}\r\n#{chunk}\r\n"
    return StringIO.new(application_chunked).read(application_chunked.size, buf)
  else
    trailers = {}
    trailers[@location_name] = @digest.base64digest
    trailers = trailers.map { |k,v| "#{k}:#{v}"}.join("\r\n")
    @trailer_io = StringIO.new("0\r\n#{trailers}\r\n\r\n")
    chunk = @trailer_io.read(length, buf)
  end
  chunk
end