fix(backend): reduce allocations in fingerprint code

[prymitive]

No description provided.

[github-actions]

Go benchmark diff

name                               old time/op        new time/op        delta
pkg:github.com/prymitive/karma/cmd/karma goos:linux goarch:amd64
Compress/Run-2                           4.96ms ± 2%        4.85ms ± 3%   -2.14%  (p=0.006 n=9+10)
Decompress/Run-2                         8.35ms ± 2%        8.40ms ± 2%     ~     (p=0.356 n=9+10)
CompressionAndDecompression/Run-2        11.5ms ± 3%        11.6ms ± 2%     ~     (p=0.063 n=10+10)
PullAlerts/0.22.0-2                      4.63ms ± 1%        3.73ms ± 3%  -19.46%  (p=0.000 n=8+10)
AlertsAPIMisses/0.22.0-2                 2.18ms ± 5%        1.39ms ± 4%  -36.36%  (p=0.000 n=10+10)
AlertsAPIMissesAutoGrid/0.22.0-2         2.26ms ± 3%        1.43ms ± 4%  -36.90%  (p=0.000 n=10+9)
AlertsAPIHits/0.22.0-2                    938µs ± 1%         937µs ± 2%     ~     (p=0.905 n=9+10)
pkg:github.com/prymitive/karma/internal/alertmanager goos:linux goarch:amd64
DedupAlerts/Run-2                         195µs ± 6%         184µs ± 2%   -5.88%  (p=0.000 n=9+9)
DedupAutocomplete/Run-2                  75.9µs ± 1%        77.5µs ± 3%   +2.08%  (p=0.001 n=9+10)
DedupColors/Run-2                        19.6µs ± 2%        19.4µs ± 1%   -0.94%  (p=0.029 n=10+10)
pkg:github.com/prymitive/karma/internal/filters goos:linux goarch:amd64
Autocomplete-2                            183ms ± 2%         184ms ± 5%     ~     (p=0.912 n=10+10)

name                               old %/compression  new %/compression  delta
pkg:github.com/prymitive/karma/cmd/karma goos:linux goarch:amd64
Compress/Run-2                             0.04 ± 0%          0.04 ± 0%     ~     (all equal)

name                               old alloc/op       new alloc/op       delta
pkg:github.com/prymitive/karma/cmd/karma goos:linux goarch:amd64
Compress/Run-2                           1.47MB ± 0%        1.47MB ± 0%     ~     (p=0.868 n=10+10)
Decompress/Run-2                         10.6MB ± 0%        10.6MB ± 0%     ~     (all equal)
CompressionAndDecompression/Run-2        12.1MB ± 0%        12.1MB ± 0%   -0.00%  (p=0.033 n=10+10)
PullAlerts/0.22.0-2                      1.30MB ± 0%        0.92MB ± 0%  -29.48%  (p=0.000 n=10+9)
AlertsAPIMisses/0.22.0-2                 1.70MB ± 0%        1.47MB ± 0%  -13.57%  (p=0.000 n=9+10)
AlertsAPIMissesAutoGrid/0.22.0-2         1.72MB ± 0%        1.47MB ± 0%  -14.29%  (p=0.000 n=10+10)
AlertsAPIHits/0.22.0-2                    293kB ± 0%         291kB ± 0%   -0.61%  (p=0.000 n=10+9)
pkg:github.com/prymitive/karma/internal/alertmanager goos:linux goarch:amd64
DedupAlerts/Run-2                         164kB ± 0%         162kB ± 0%   -1.34%  (p=0.000 n=10+10)
DedupAutocomplete/Run-2                  44.0kB ± 0%        44.0kB ± 0%     ~     (p=0.511 n=10+10)
DedupColors/Run-2                        11.0kB ± 0%        11.0kB ± 0%     ~     (all equal)
pkg:github.com/prymitive/karma/internal/filters goos:linux goarch:amd64
Autocomplete-2                           71.8MB ± 0%        71.8MB ± 0%     ~     (p=0.497 n=10+9)

name                               old allocs/op      new allocs/op      delta
pkg:github.com/prymitive/karma/cmd/karma goos:linux goarch:amd64
Compress/Run-2                             28.5 ± 2%          28.5 ± 2%     ~     (p=1.000 n=10+10)
Decompress/Run-2                            107 ± 0%           107 ± 0%     ~     (all equal)
CompressionAndDecompression/Run-2           138 ± 0%           138 ± 0%     ~     (p=0.087 n=10+10)
PullAlerts/0.22.0-2                       23.6k ± 0%         16.7k ± 0%  -29.04%  (p=0.001 n=8+9)
AlertsAPIMisses/0.22.0-2                  7.10k ± 0%         3.01k ± 0%  -57.66%  (p=0.000 n=10+10)
AlertsAPIMissesAutoGrid/0.22.0-2          6.96k ± 0%         2.87k ± 0%  -58.86%  (p=0.000 n=10+10)
AlertsAPIHits/0.22.0-2                    2.28k ± 0%         2.27k ± 0%   -0.31%  (p=0.000 n=10+10)
pkg:github.com/prymitive/karma/internal/alertmanager goos:linux goarch:amd64
DedupAlerts/Run-2                           909 ± 0%           875 ± 0%   -3.74%  (p=0.000 n=10+10)
DedupAutocomplete/Run-2                     136 ± 0%           136 ± 0%     ~     (all equal)
DedupColors/Run-2                          51.0 ± 0%          51.0 ± 0%     ~     (all equal)
pkg:github.com/prymitive/karma/internal/filters goos:linux goarch:amd64
Autocomplete-2                            1.60M ± 0%         1.60M ± 0%     ~     (p=0.562 n=10+9)