optimization: Use event notification to synchronize threads

[akiradeveloper]

No description provided.

[akiradeveloper]

We see a x100 improvement and it's reasonable. Let's go merge.

test commit_n1_m1    ... bench: 220,030,854.60 ns/iter (+/- 51,112,128.60)
test commit_n1_m10   ... bench: 260,102,900.20 ns/iter (+/- 80,138,739.06)
test commit_n1_m100  ... bench: 200,468,241.90 ns/iter (+/- 60,057,024.29)
test commit_n1_m1000 ... bench: 337,614,414.50 ns/iter (+/- 155,721,911.66)
test commit_n3_m1    ... bench: 219,874,339.60 ns/iter (+/- 40,089,901.74)
test commit_n3_m10   ... bench: 279,845,786.20 ns/iter (+/- 61,609,707.33)

=>

test commit_n1_m1    ... bench:   1,158,107.04 ns/iter (+/- 554,816.50)
test commit_n1_m10   ... bench:   2,215,039.10 ns/iter (+/- 2,060,375.24)
test commit_n1_m100  ... bench:  17,434,569.50 ns/iter (+/- 10,195,007.00)
test commit_n1_m1000 ... bench: 238,663,680.10 ns/iter (+/- 108,996,584.86)
test commit_n3_m1    ... bench:   1,287,702.09 ns/iter (+/- 934,619.03)
test commit_n3_m10   ... bench:   3,402,119.55 ns/iter (+/- 1,738,369.64)