Unlike Proton, Proton-J does not provide SASL frame trace if environment variable PN_TRACE_FRM is set. It would be useful if Proton-J had this ability too to help diagnose SASL negotiation problem.
Proton's SASL frame trace looks like this:
[0x7fc112c03a00]: -> SASL
[0x7fc112c03a00]: <- SASL
[0x7fc112c03a00]:0 <- @sasl-mechanisms(64) [sasl-server-mechanisms=@PN_SYMBOL[:ANONYMOUS]]
[0x7fc112c03a00]:0 -> @sasl-init(65) [mechanism=:ANONYMOUS, initial-response=b"guest@Oslo.local"]
[0x7fc112c03a00]:0 <- @sasl-outcome(68) [code=0]
[0x7fc112c03a00]: -> AMQP
[0x7fc112c03a00]:0 -> @open(16) [container-id="be777c26-af6e-4935-a6be-316cc8bbdb35", hostname="127.0.0.1", channel-max=32767]
The "SASL" and "AMQP" notices to mark send/receive of the associated headers are similarly omitted by proton-j and would be useful to add.