fix(network): show what causes the test failure

[hannahhoward]

Goals

Diagnose issue in test failure after upgrading libp2p from 0.16.1 -> 0.20.1.

Implementation

it appears calling stream.Close() too quickly returns an error? Adding a sleep fixes the problem. However, I don't understand why stream.Close would emit an error if you call it right after sending data.

cc: @marten-seemann @aschmahmann

[hannahhoward]

Follow up: this issue does NOT occur when doing a straight upgrade to v0.19.4 without going to 0.20.1 first. So I believe there is a transitive dependency difference between 0.19.4 and 0.20.1 that is the problem