Review use of Lambda and strong outer class reference

[smaldini]

Currently we loosely use lambda ( " -> ") in many places but we should carefully review what references are we keeping doing so. For instance a simple eventLoop.execute(() -> xxxx) might prevent the outer state being garbage collected where we could use a static final class InnerClass instead transporting the exact references required for the task.
Sometimes all the outer state makes sense and therefore lambda might just be fine.