`wait()`

[loreanvictor]

a good number of actions are covered by check() aliases, i.e. in most cases you want to either validate something, check some permissions, or find some data. however, there is a lack of a generic just do this and wait for when its done operator (so an equivalent of tap() that would wait until its task is finished), i.e. wait(). it would be extremely convenient if wait() acted exactly like tap(), except that it would wait for async functions or inner observables first emissions and then pass down incoming emissions.