usable traces across workers

[dckc]

What is the Problem Being Solved?

With the endo daemon coordinating several workers, errors usually result in unhelpful stack traces that basically say "I got an Error over CapTP":

$ endo make src/hdWallet.js -n w1
CapTP cli exception: (RemoteSyntaxError(error:captp:Endo#20001)#1)
RemoteSyntaxError(error:captp:Endo#20001)#1: Possible direct eval expression rejected at <unknown>:12. (SES_EVAL_REJECTED)

  at decodeErrorCommon (packages/marshal/src/marshal.js:281:28)
  at decodeErrorFromCapData (packages/marshal/src/marshal.js:297:14)
  at decodeFromCapData (packages/marshal/src/encodeToCapData.js:404:27)
  at fromCapData (packages/marshal/src/marshal.js:359:23)
  at CTP_RETURN (packages/captp/src/captp.js:697:24)
  at dispatch (packages/captp/src/captp.js:776:7)
  at packages/daemon/src/connection.js:34:7

Description of the Design

@kriskowal suggests a causal trace aggregator

See also:

• https://github.com/Agoric/agoric-sdk/issues/1864

Security Considerations

censoring the right parts of the stack is tricky, I expect; moreso across workers

Scaling Considerations

ISTR some scaling issues around "track turns".

Test Plan

???

Upgrade Considerations

I'm using the endo cli / daemon on the endo branch.

[kriskowal]

See https://github.com/endojs/endo/issues/529 for issue in general.