docs: function write_binary_type(out, opts) {
  	switch(opts.type) {
  		case "string":
  		case "base64":
  		case "binary":
  			var bstr = "";
  			// $FlowIgnore
  			for(var i = 0; i < out.length; ++i) bstr += String.fromCharCode(out[i]);
  			return opts.type == 'base64' ? Base64.encode(bstr) : opts.type == 'string' ? utf8read(bstr) : bstr;
  		case "file": return write_dl(opts.file, out);
  		case "buffer": return out;
  		default: throw new Error("Unrecognized type " + opts.type);
  	}
  }