/home/travis/.nvm/versions/node/v8.1.0/bin/node[3346]: ../src/env-inl.h:131:void node::Environment::AsyncHooks::push_ids(double, double): Assertion `(trigger_id) >= (0)' failed.
 1: node::Abort() [node]
 2: node::Assert(char const* const (*) [4]) [node]
 3: node::AsyncWrap::PushAsyncIds(v8::FunctionCallbackInfo<v8::Value> const&) [node]
 4: v8::internal::FunctionCallbackArguments::Call(void (*)(v8::FunctionCallbackInfo<v8::Value> const&)) [node]
 5: 0xb43f48 [node]
 6: v8::internal::Builtin_HandleApiCall(int, v8::internal::Object**, v8::internal::Isolate*) [node]
 7: 0x26285a08437d
Aborted (core dumped)