* netxlite: improve docs, tests, and code quality
* better documentation
* more strict testing of dialer (especially make sure we
document the quirk in https://github.com/ooni/probe/issues/1779
and we have tests to guarantee we don't screw up here)
* introduce NewErrWrapper factory for creating errors so we
have confidence we are creating them correctly
Part of https://github.com/ooni/probe/issues/1591
They are now more readable. I'll do another pass and start
separating integration testing from unit testing.
I think we need to have some always on integration testing
for netxlite that runs on macOS, linux, and windows.
See https://github.com/ooni/probe/issues/1591
The legacy part for now is internal/errorsx. It will stay there until
I figure out whether it also needs some extra bug fixing.
The good part is now in internal/netxlite/errorsx and contains all the
logic for mapping errors. We need to further improve upon this logic
by writing more thorough integration tests for QUIC.
We also need to copy the various dialer, conn, etc adapters that set
errors. We will put them inside netxlite and we will generate errors in
a way that is less crazy with respect to the major operation. (The
idea is to always wrap, given that now we measure in an incremental way
and we don't measure every operation together.)
Part of https://github.com/ooni/probe/issues/1591
This quirk really saddens me. It's a piece of tech debt we're
carrying over from the original netx implementation.
We cannot remove it _until_ we have legacy netx code around.
The second best thing we can do is to clearly move this code in
a place where it's clear it's a quirk and write and use some extra
code that makes sure the quirk's assumptions are always met.
Sigh.
See https://github.com/ooni/probe/issues/1591
