humility network error messages could provide more context

[rmustacc]

I was trying to run capture a dump from an SP that is broadcasting, but not accepting comms:

rm@jeeves ~ $ pfexec humility -i fe80::aa40:25ff:fe04:346%e1000g0 -a /net/catacomb/data/staff/dock/rack2/gimlet/c/sp/gimlet-c-perst-spec-viol.zip dump
humility: connecting to fe80::aa40:25ff:fe04:346%e1000g0
humility dump failed: Resource temporarily unavailable (os error 11)

From the output of truss this is a call to recv getting EAGAIN:

send(3, " = wAE %DA889B Q17\001\0".., 21, 0)    = 21
recv(3, 0xFFFFFC7FFFDFBFC0, 1024, 0) (sleeping...)
recv(3, 0xFFFFFC7FFFDFBFC0, 1024, 0)            Err#11 EAGAIN

Having the context that it was the network would have sped this up

[cbiffle]

Oh goodness, yes, this is another case where we failed to use anyhow::Context to annotate. Sorry about that.

[rmustacc]

For additional here is a mangled (sorry about that) stack trace of where this is coming from in case it's relevant:

rm@jeeves ~ $ pfexec dtrace -n 'syscall::recv:return/errno == 11/{ ustack(); }' -p $(pgrep humility)
dtrace: description 'syscall::recv:return' matched 1 probe
dtrace: pid 21293 has exited
CPU     ID                    FUNCTION:NAME
  0   5623                      recv:return 
              libc.so.1`0xfffffc7fee8e757a
              libsocket.so.1`0xfffffc7fef3a1cc2
              humility-0.9.29`_ZN3std3net3udp9UdpSocket4recv17h8d6518aa19c7af1dE+0x18
              humility-0.9.29`_ZN74_$LT$humility_core..core..NetCore$u20$as$u20$humility_core..core..Core$GT$4recv17h9f0fd83e17fe1a29E+0x19
              humility-0.9.29`_ZN3std6thread5local17LocalKey$LT$T$GT$4with17h414f05101d011343E+0x1d4
              humility-0.9.29`_ZN12humility_cmd5hiffy12HiffyContext11perform_rpc13hiffy_send_fn17h8c2d1112b59e0341E+0x1fa
              humility-0.9.29`_ZN3hif7execute17hb76bf5e41e9c84d8E+0x272
              humility-0.9.29`_ZN12humility_cmd5hiffy12HiffyContext5start17h64bc83f1b17f2ef8E+0x7a0
              humility-0.9.29`_ZN12humility_cmd5hiffy12HiffyContext3run17h7c7136ff9e1d46dbE+0x40
              humility-0.9.29`_ZN18humility_cmd_hiffy10hiffy_call17hc546cbfebee3ad79E+0x35f
              humility-0.9.29`_ZN18humility_cmd_hiffy5hiffy17h078d5d3436cc1437E+0x15dd
              humility-0.9.29`_ZN8humility3cmd10subcommand17h352726086863d293E+0x49f
              humility-0.9.29`_ZN8humility4main17hd1ee2b6b5738251cE+0xc5c
              humility-0.9.29`_ZN3std10sys_common9backtrace28__rust_begin_short_backtrace17h692176f518497981E+0x6
              humility-0.9.29`_ZN3std2rt10lang_start28_$u7b$$u7b$closure$u7d$$u7d$17hfcede5d2d46d0f5dE.llvm.5675738150128816373+0x15
              humility-0.9.29`_ZN3std2rt19lang_start_internal17h2552018c550f522bE+0x2b0
              humility-0.9.29`main+0x36
              humility-0.9.29`_start_crt+0x87
              humility-0.9.29`_start+0x18