Properties
defaultOptions?
handlers?
roots?
versionNegotiation?
ClientOptions.versionNegotiation on the single-server Client — same
semantics, just applied per sub-client here since each connected server
negotiates its own era independently. Default { mode: 'auto' }: each
sub-client probes its server once and falls back to legacy when the
server offers no modern era; { mode: 'legacy' } opts every connection
out of the probe.