Test Pandas Series is writeable

[jakirkham]

Follow-up to PR ( #3967 ) and issue ( #3943 )

Includes a test to ensure a Pandas Series is writeable after round-trip serialization.

[quasiben]

Looks like this is failing on the test submitted in the PR:
https://travis-ci.org/github/dask/distributed/jobs/712415247#L1560

[jakirkham]

Yeah I saw that last night. This is weird as it passed locally. Will look into it.

[mrocklin]

Checking in. Do we know what happened here? I ran into buffer source array is read-only errors on 2.21.0 recently and I'm curious if our latest release is broken.

[jakirkham]

The fix got merged after the last release unfortunately ( #3967 ). I suppose we could push out a patch release with that fix. Though we are planning to release tomorrow ( dask/community#77 )

A separate question is why this test doesn't work. Though people have already confirmed that PR does.

[mrocklin]

Ah ok, so we just need to release. Grand. Thanks @jakirkham !

[jakirkham]

This test was included as part of PR ( #4004 ).