According to `rend-spec.txt`: ``` When uploading descriptors, the hidden service needs to make sure that descriptors for different clients are not uploaded at the same time (cf. Section 1.1) which is also a limiting factor for the number of clients. ``` At the moment it's unclear how it should be implemented and why. * What is the threat model here? * How exactly descriptors should be uploaded? * In what range delays should be set? * How this will work along with absent delays after legacy/trac#20082?