class Gem::Package::DigestIO

def self.wrap io, digests
  digest_io = new io, digests
  yield digest_io
  return digests
end

def initialize io, digests
  @io = io
  @digests = digests
end

def write data
  result = @io.write data
  @digests.each do |_, digest|
    digest << data
  end
  result
end