class Gem::Package::DigestIO

def self.wrap(io, digests)
  digest_io = new io, digests
  yield digest_io
  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