title: Is possible to add capture values to lambda when do DatabaseReference::RunTransaction?
body: <p>I work with Firebase Realtime Database and want do add value to my vector in transacation, i.e. get vector, update, set vector.</p>
  
  <p>I write some simple labda, but stuck with that code wont compiles.</p>
  
  <pre><code>    auto transaction  = [&amp;key](firebase::database::MutableData* data){
      auto value = data-&gt;GetValue();
      if(!value.is_vector() or value.is_null())
          return firebase::database::kTransactionResultAbort;
      std::vector&lt;firebase::Variant&gt; taskList = value.vector();
      //!!    taskList.push_back(firebase::Variant(key)); !!//
      data-&gt;SetValue(firebase::Variant(taskList));
      return firebase::database::kTransactionResultSuccess;
  };
  dbref.Child("/users/" +userId+ "/tasks/").RunTransaction(transaction);
  </code></pre>
  
  <p>I wonna to add param to that labda. Can I do it in another way?</p>
  
  <p>Compiller errors:</p>
  
  <pre><code>    tasksmanager.cpp:62:72: error: no matching function for call to 'firebase::database::DatabaseReference::RunTransaction(TasksManager::createTask(Task*)::&lt;lambda(firebase::database::MutableData*)&gt;&amp;)'
       dbref.Child("/users/" +userId+ "/tasks/" + key).RunTransaction(tran);
                                                                          ^
  tasksmanager.cpp:62:72: note: candidate is:
  In file included from ..\firebase_cpp_sdk\include/firebase/database.h:9:0,
                   from tasksmanager.cpp:2:
  ..\firebase_cpp_sdk\include/firebase/database/database_reference.h:178:24: note: firebase::Future&lt;firebase::database::DataSnapshot&gt; firebase::database::DatabaseReference::RunTransaction(firebase::database::TransactionResult (*)(firebase::database::MutableData*), bool)
     Future&lt;DataSnapshot&gt; RunTransaction(DoTransaction* transaction_function,
                          ^
  ..\firebase_cpp_sdk\include/firebase/database/database_reference.h:178:24: note:   no known conversion for argument 1 from 'TasksManager::createTask(Task*)::&lt;lambda(firebase::database::MutableData*)&gt;' to 'firebase::database::TransactionResult (*)(firebase::database::MutableData*)'
  </code></pre>