# File lib/celluloid/io.rb, line 39
    def self.copy_stream(src, dst, copy_length = nil, src_offset = nil)
      fail NotImplementedError, "length/offset not supported" if copy_length || src_offset

      src, dst = try_convert(src), try_convert(dst)

      # FIXME: this always goes through the reactor, and can block on file I/O
      while data = src.read(BLOCK_SIZE)
        dst << data
      end
    end