fix(collection): handle creating model when connection disconnected with bufferCommands = false

[vkarpov15]

Summary

If you create a new model while Mongoose is disconnected, and bufferCommands is false, you'll get the following error:

MongooseError: Cannot call `tests.findOne()` before initial connection is complete if `bufferCommands = false`. Make sure you `await mongoose.connect()` if you have `bufferCommands = false`.

That is unexpected. You should never get that error after calling mongoose.connect(), even with bufferCommands disabled.

Examples

[hasezoey]

LGTM, though i am not quite sure what this is solving

i am currently understating it as "creating a model (mongoose.model) after the connection was connected once but is not at the point of model creation while bufferCommands is false"?

[vkarpov15]

Here's a quick overview of when this issue happens:

1. mongoose.connect() succeeds, bufferCommands is set to false
2. Mongoose loses connectivity to the database. Perhaps the MongoDB server went down, or there's a network outage.
3. Create a new model using mongoose.model()
4. Run await Model.findOne(), get error about initial connection

[IslandRhythms]

LGTM