* 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
This simplifies serializing errors to `*string`. It did not
occur to me before. It seems quite a nice improvement.
Part of https://github.com/ooni/probe/issues/1591
No real functional change. A few are needed and they will come
next. With this diff I just wanted to do cosmetic changes and
documentation changes, to ensure this package is okay.
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
