Type annotations misinterpreted by phpstan

[christiaan]

When using this library in a project which uses phpstan for code analysis it gives the following error.

Call to method then() on an unknown class     
React\Socket\React\Promise\PromiseInterface. 

This happens because of the following return type @return React\Promise\PromiseInterface of ConnectorInterface#connect

Since the file is namespaced it expects all types to either be relative to the file namespace or to start with a \ if you want a fully qualified name.