Backport PR #892 on branch 1.x (Make ChannelQueue.get_msg true async)

[meeseeksmachine]

Backport PR #892: Make ChannelQueue.get_msg true async

[codecov-commenter]

Codecov Report

Merging #893 (80103b3) into 1.x (5cf2b40) will increase coverage by 0.25%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##              1.x     #893      +/-   ##
==========================================
+ Coverage   70.42%   70.67%   +0.25%     
==========================================
  Files          62       62              
  Lines        7655     7670      +15     
  Branches     1270     1273       +3     
==========================================
+ Hits         5391     5421      +30     
+ Misses       1880     1863      -17     
- Partials      384      386       +2     

Impacted Files	Coverage Δ
jupyter_server/gateway/managers.py	63.84% <100.00%> (+3.73%)	⬆️
jupyter_server/services/kernels/kernelmanager.py	80.58% <0.00%> (+1.94%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 5cf2b40...80103b3. Read the comment docs.