Sleep between events if PoH is disabled

[garious]

No description provided.

[codecov]

Codecov Report

Merging #286 into master will decrease coverage by 0.98%.
The diff coverage is 91.83%.

@@            Coverage Diff            @@
##           master    #286      +/-   ##
=========================================
- Coverage   89.49%   88.5%   -0.99%     
=========================================
  Files          32      32              
  Lines        2960    2985      +25     
=========================================
- Hits         2649    2642       -7     
- Misses        311     343      +32

Impacted Files	Coverage Δ
src/tpu.rs	93.93% <83.33%> (-2.49%)	⬇️
src/record_stage.rs	88.07% <93.02%> (+0.43%)	⬆️
src/streamer.rs	82.32% <0%> (-5.81%)	⬇️
src/crdt.rs	70.17% <0%> (-1.72%)	⬇️

---

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 a8e1c44...fb33a83. Read the comment docs.