Add notes for testing on windows

[zanieb]

No description provided.

[konstin]

For anyone who comes looking at this in future: The cause is that nested futures in debug mode are massive, while they get compiled down to a reasonable size in release mode. You can debug this with some variation of (unix only). Install from https://github.com/loyd/top-type-sizes:

RUSTFLAGS=-Zprint-type-sizes cargo +nightly build -p uv -j 1 > type-sizes.txt && top-type-sizes -w -s -h 10 < type-sizes.txt > sizes.txt

You can debug the overflowing stack with lldb using https://forums.swift.org/t/getting-stack-size-using-lldb/63207:

settings set frame-format "frame #${frame.index}: sp=${frame.sp} fp=${frame.fp} pc=${frame.pc}{ ${module.file.basename}{`${function.name-with-args}${function.pc-offset}}}{ at ${line.file.basename}:${line.number}}{${function.is-optimized} [opt]}\n"
thread backtrace
session save backtrace.txt

Feed this to https://gist.github.com/konstin/448492d131bd346f2d387257c47fa312 to get the stack frame sizes.