refactor: refactor offline geocoder to use prefixmap similar to java version

[wmundev]

• migrate offline geocoder to use prefixFileReader like java version
• update implementation of several methods to match java version

[codecov]

Codecov Report

❌ Patch coverage is 80.00000% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 75.63%. Comparing base (4349c46) to head (e0e6dbe).

Files with missing lines	Patch %	Lines
csharp/PhoneNumbers/PhoneNumberOfflineGeocoder.cs	80.48%	7 Missing and 1 partial ⚠️
csharp/PhoneNumbers/PhoneNumberUtil.cs	66.66%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #334      +/-   ##
==========================================
- Coverage   75.79%   75.63%   -0.17%     
==========================================
  Files          40       40              
  Lines        4731     4712      -19     
  Branches     1119     1115       -4     
==========================================
- Hits         3586     3564      -22     
- Misses        914      917       +3     
  Partials      231      231              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[github-actions]

✔️ Benchmark Results

No significant performance change vs. main
Commit: e0e6dbe · Full run · Windows windows-latest
🟢 improved >5% · 🟡 neutral ±5% · 🔴 regressed >5% · lower is better for both time and allocation

📊 Comparison vs. main

Method	Runtime	PhoneNumberCount	main Mean	PR Mean	Time Δ	main Alloc	PR Alloc	Alloc Δ	Status
ParseValidateAndFormatPhoneNumbers	.NET 8.0	1000	2.789 ms	2.868 ms	🟡 +2.8%	581.63 KB	581.63 KB	🟡 +0.0%	🟡 Neutral
ParseValidateAndFormatPhoneNumbers	.NET 8.0	10000	28.216 ms	28.097 ms	🟡 -0.4%	5.67 MB	5.67 MB	🟡 +0.0%	🟡 Neutral
ParseValidateAndFormatPhoneNumbers	.NET 8.0	100000	294.651 ms	289.911 ms	🟡 -1.6%	56.73 MB	56.73 MB	🟡 +0.0%	🟡 Neutral
ParseValidateAndFormatPhoneNumbers	.NET 9.0	1000	2.658 ms	2.679 ms	🟡 +0.8%	581.63 KB	581.63 KB	🟡 +0.0%	🟡 Neutral
ParseValidateAndFormatPhoneNumbers	.NET 9.0	10000	27.159 ms	26.835 ms	🟡 -1.2%	5.67 MB	5.67 MB	🟡 +0.0%	🟡 Neutral
ParseValidateAndFormatPhoneNumbers	.NET 9.0	100000	271.141 ms	269.517 ms	🟡 -0.6%	56.73 MB	56.73 MB	🟡 +0.0%	🟡 Neutral
ParseValidateAndFormatPhoneNumbers	.NET Framework 4.8	1000	8.025 ms	7.886 ms	🟡 -1.7%	1.37 MB	1.36 MB	🟡 -0.0%	🟡 Neutral
ParseValidateAndFormatPhoneNumbers	.NET Framework 4.8	10000	81.925 ms	79.757 ms	🟡 -2.6%	13.63 MB	13.63 MB	🟡 +0.0%	🟡 Neutral
ParseValidateAndFormatPhoneNumbers	.NET Framework 4.8	100000	809.062 ms	827.629 ms	🟡 +2.3%	136.26 MB	136.26 MB	🟡 +0.0%	🟡 Neutral

📋 Full Results — PR branch

Method	Job	Runtime	PhoneNumberCount	Mean	Error	StdDev	Gen0	Gen1	Allocated
ParseValidateAndFormatPhoneNumbers	.NET 8.0	.NET 8.0	1000	2.868 ms	11.935 μs	44.656 μs	6.0000	-	581.63 KB
ParseValidateAndFormatPhoneNumbers	.NET 8.0	.NET 8.0	10000	28.097 ms	54.650 μs	204.481 μs	7.0000	-	5.67 MB
ParseValidateAndFormatPhoneNumbers	.NET 8.0	.NET 8.0	100000	289.911 ms	1.481 ms	6.947 ms	4.0000	-	56.73 MB
ParseValidateAndFormatPhoneNumbers	.NET 9.0	.NET 9.0	1000	2.679 ms	8.871 μs	34.357 μs	6.0000	-	581.63 KB
ParseValidateAndFormatPhoneNumbers	.NET 9.0	.NET 9.0	10000	26.835 ms	66.151 μs	247.514 μs	7.0000	-	5.67 MB
ParseValidateAndFormatPhoneNumbers	.NET 9.0	.NET 9.0	100000	269.517 ms	573.196 μs	2.067 ms	4.0000	-	56.73 MB
ParseValidateAndFormatPhoneNumbers	.NET Framework 4.8	.NET Framework 4.8	1000	7.886 ms	38.580 μs	172.536 μs	29.0000	3.0000	1.36 MB
ParseValidateAndFormatPhoneNumbers	.NET Framework 4.8	.NET Framework 4.8	10000	79.757 ms	365.230 μs	1.367 ms	15.0000	1.0000	13.63 MB
ParseValidateAndFormatPhoneNumbers	.NET Framework 4.8	.NET Framework 4.8	100000	827.629 ms	3.764 ms	14.579 ms	22.0000	2.0000	136.26 MB

📋 Full Results — main branch

Method	Job	Runtime	PhoneNumberCount	Mean	Error	StdDev	Gen0	Gen1	Allocated
ParseValidateAndFormatPhoneNumbers	.NET 8.0	.NET 8.0	1000	2.789 ms	7.712 μs	29.870 μs	6.0000	-	581.63 KB
ParseValidateAndFormatPhoneNumbers	.NET 8.0	.NET 8.0	10000	28.216 ms	66.343 μs	248.231 μs	7.0000	-	5.67 MB
ParseValidateAndFormatPhoneNumbers	.NET 8.0	.NET 8.0	100000	294.651 ms	1.486 ms	6.647 ms	4.0000	-	56.73 MB
ParseValidateAndFormatPhoneNumbers	.NET 9.0	.NET 9.0	1000	2.658 ms	3.356 μs	11.625 μs	6.0000	-	581.63 KB
ParseValidateAndFormatPhoneNumbers	.NET 9.0	.NET 9.0	10000	27.159 ms	84.839 μs	317.439 μs	7.0000	-	5.67 MB
ParseValidateAndFormatPhoneNumbers	.NET 9.0	.NET 9.0	100000	271.141 ms	361.163 μs	1.351 ms	4.0000	-	56.73 MB
ParseValidateAndFormatPhoneNumbers	.NET Framework 4.8	.NET Framework 4.8	1000	8.025 ms	40.430 μs	180.811 μs	14.0000	1.0000	1.37 MB
ParseValidateAndFormatPhoneNumbers	.NET Framework 4.8	.NET Framework 4.8	10000	81.925 ms	344.564 μs	1.334 ms	15.0000	1.0000	13.63 MB
ParseValidateAndFormatPhoneNumbers	.NET Framework 4.8	.NET Framework 4.8	100000	809.062 ms	3.752 ms	14.040 ms	22.0000	2.0000	136.26 MB