adds code-path broadcasting shreds using QUIC

[behzadnouri]

Problem

Turbine => QUIC migration

Summary of Changes

• Added code-path broadcasting shreds using QUIC.
• Currently this code-path is inactive for all shreds.
• We will incrementally roll-out and monitor shreds propagation using QUIC.

[codecov]

Codecov Report

Merging #31610 (944cb26) into master (2572df7) will decrease coverage by 0.1%.
The diff coverage is 67.8%.

@@            Coverage Diff            @@
##           master   #31610     +/-   ##
=========================================
- Coverage    81.9%    81.9%   -0.1%     
=========================================
  Files         764      765      +1     
  Lines      208096   208248    +152     
=========================================
+ Hits       170507   170631    +124     
- Misses      37589    37617     +28     

[joncinque]

The changes look good, just a few nits and questions. And then the larger question from #31576 about whether this should be included in 1.16. It would be better to include it, but we'll need to start telling operators to start opening the new port immediately.

If it's in 1.16, we'd likely avoid the situation of needing to make a 1.13-style branch just to force Turbine over QUIC. You probably have a clearer plan, but it could look like:

• 1.16: validators open the port and can receive it, helping the 1.16 to 1.17 transition
• 1.17: cut over to only QUIC
• 1.18: shut off UDP

Let me know if I should post this elsewhere

[joncinque]

Looks good to me!

[t-nelson]

how much of this stuff really needs to be in master before we know for a fact that quic is suited for the job? i don't want to be in a situation where we have a bunch of gaps in abi and special-case logic because we got ahead of ourselves and committed code that was doomed to be abandoned