…as default.

This will speed up checksum calculation during writes.

…ed maps.

Benchmarks:
```
synchronizer/write      time:   [17.183 µs 17.387 µs 17.647 µs]
                        thrpt:  [56.666 Kelem/s 57.515 Kelem/s 58.195 Kelem/s]
                 change:
                        time:   [-47.134% -45.506% -43.898%] (p = 0.00 < 0.05)
                        thrpt:  [+78.247% +83.508% +89.156%]
                        Performance has improved.
synchronizer/write_raw  time:   [147.12 ns 147.76 ns 148.57 ns]
                        thrpt:  [6.7310 Melem/s 6.7676 Melem/s 6.7970 Melem/s]
                 change:
                        time:   [-98.463% -98.442% -98.422%] (p = 0.00 < 0.05)
                        thrpt:  [+6236.1% +6320.0% +6405.5%]
                        Performance has improved.
synchronizer/read/check_bytes_true
                        time:   [41.194 ns 41.271 ns 41.369 ns]
                        thrpt:  [24.172 Melem/s 24.230 Melem/s 24.275 Melem/s]
                 change:
                        time:   [-0.3344% +0.8124% +1.6734%] (p = 0.12 > 0.05)
                        thrpt:  [-1.6458% -0.8058% +0.3355%]
                        No change in performance detected.
synchronizer/read/check_bytes_false
                        time:   [26.658 ns 26.668 ns 26.685 ns]
                        thrpt:  [37.475 Melem/s 37.498 Melem/s 37.513 Melem/s]
                 change:
                        time:   [-4.4520% -3.5968% -2.8378%] (p = 0.00 < 0.05)
                        thrpt:  [+2.9206% +3.7309% +4.6595%]
                        Performance has improved.
```

Also added template parameter `N` for scratch space size.

Benchmarks:
```
synchronizer/write      time:   [250.71 ns 251.42 ns 252.41 ns]
                        thrpt:  [3.9619 Melem/s 3.9774 Melem/s 3.9887 Melem/s]
                 change:
                        time:   [-99.152% -99.147% -99.142%] (p = 0.00 < 0.05)
                        thrpt:  [+11559% +11627% +11699%]
                        Performance has improved.
synchronizer/write_raw  time:   [145.25 ns 145.53 ns 145.92 ns]
                        thrpt:  [6.8531 Melem/s 6.8717 Melem/s 6.8849 Melem/s]
                 change:
                        time:   [-98.508% -98.471% -98.443%] (p = 0.00 < 0.05)
                        thrpt:  [+6322.7% +6441.2% +6602.9%]
                        Performance has improved.
synchronizer/read/check_bytes_true
                        time:   [40.114 ns 40.139 ns 40.186 ns]
                        thrpt:  [24.884 Melem/s 24.914 Melem/s 24.929 Melem/s]
                 change:
                        time:   [-0.1031% -0.0200% +0.0753%] (p = 0.69 > 0.05)
                        thrpt:  [-0.0752% +0.0200% +0.1032%]
                        No change in performance detected.
synchronizer/read/check_bytes_false
                        time:   [26.658 ns 26.673 ns 26.696 ns]
                        thrpt:  [37.458 Melem/s 37.491 Melem/s 37.512 Melem/s]
                 change:
                        time:   [-0.9845% -0.9083% -0.7959%] (p = 0.00 < 0.05)
                        thrpt:  [+0.8023% +0.9167% +0.9943%]
                        Change within noise threshold.
```

… `1.0.3`.