dynamic delegate(Invocation invocation)

Performs invocation on reflectee.

Equivalent to

if (invocation.isGetter) {
  return this.getField(invocation.memberName).reflectee;
} else if (invocation.isSetter) {
  return this.setField(invocation.memberName,
                       invocation.positionArguments[0]).reflectee;
} else {
  return this.invoke(invocation.memberName,
                     invocation.positionalArguments,
                     invocation.namedArguments).reflectee;
}

Source 

delegate(Invocation invocation);