"Delay my HTLC" option

[TheBlueMatt]

Peter Todd suggested on the ML having an option to tell peers you'd rather your HTLC be delayed for improved privacy than clear quickly. While obviously nodes don't want to hold HTLCs longer than they have to, swapping out the batching delay for such HTLCs from, eg, 100ms to 1s would make sense. The obvious tradeoff is you start giving out a "I'm just a rebalancing" bit on your HTLCs, potentially telling routing nodes about your payments with more accuracy.