bindBinaryCallback abstract method 
  ZoneBinaryCallback<R, T1, T2> bindBinaryCallback<R, T1, T2>(Equivalent to:
 ZoneCallback registered = registerBinaryCallback(action);
 if (runGuarded) {
   return (arg1, arg2) => this.runBinaryGuarded(registered, arg);
 }
 return (arg1, arg2) => thin.runBinary(registered, arg1, arg2);
   Source
ZoneBinaryCallback<R, T1, T2> bindBinaryCallback<R, T1, T2>(
    R action(T1 argument1, T2 argument2),
    {bool runGuarded: true});
    © 2012 the Dart project authors
Licensed under the Creative Commons Attribution-ShareAlike License v4.0.
    https://api.dartlang.org/stable/1.24.3/dart-async/Zone/bindBinaryCallback.html