Fix issue where the last letter of self-send messages would get dropped

[ErisApps]

Fixes #73

This apparently also slightly improved the performance of the logic responsible for splitting up multiple raw irc messages.

Benchmark result comparing the old logic with the newly fixed logic.

BenchmarkDotNet=v0.13.4, OS=Windows 10 (10.0.19044.2604/21H2/November2021Update) AMD Ryzen 9 3900X, 1 CPU, 24 logical and 12 physical cores [Host] : .NET Framework 4.8 (4.8.4614.0), X64 RyuJIT VectorSize=256 Job-CIRMVA : .NET 5.0.17 (5.0.1722.21314), X64 RyuJIT AVX2 Job-NVAYXH : .NET 6.0.14 (6.0.1423.7309), X64 RyuJIT AVX2 Job-ZSFKTD : .NET Framework 4.8 (4.8.4614.0), X64 RyuJIT VectorSize=256 Job-XTWDPN : Mono 5.11.0 (Visual Studio), X86 VectorSize=128 Job-UGEEKR : Mono 6.13.0 (Visual Studio), X86 VectorSize=128 Job-LJOXDK : Mono 6.13.0 (Visual Studio), X86 VectorSize=128

Method	Runtime	RawIrcMultiMessage	Mean	Error	StdDev	StdErr	Min	Q1	Median	Q3	Max	Op/s	Ratio	Baseline	Gen0	Allocated	Alloc Ratio
InlineSpanBasedSplitBenchmarkFeexed	.NET 5.0	:tmi(...)TE\r\n [528]	1,131.7 ns	6.89 ns	6.11 ns	1.63 ns	1,121.1 ns	1,127.6 ns	1,131.8 ns	1,135.7 ns	1,141.7 ns	883,643.8	0.77	No	0.2728	2288 B	1.00
InlineSpanBasedSplitBenchmark	.NET 5.0	:tmi(...)TE\r\n [528]	1,478.4 ns	16.42 ns	14.56 ns	3.89 ns	1,461.9 ns	1,467.9 ns	1,471.4 ns	1,486.1 ns	1,505.1 ns	676,419.4	1.00	Yes	0.2728	2288 B	1.00
InlineSpanBasedSplitBenchmarkFeexed	.NET 6.0	:tmi(...)TE\r\n [528]	998.5 ns	8.33 ns	7.38 ns	1.97 ns	988.0 ns	992.2 ns	998.1 ns	1,002.5 ns	1,015.3 ns	1,001,513.5	0.84	No	0.2728	2288 B	1.00
InlineSpanBasedSplitBenchmark	.NET 6.0	:tmi(...)TE\r\n [528]	1,193.6 ns	9.76 ns	8.66 ns	2.31 ns	1,177.8 ns	1,187.8 ns	1,193.2 ns	1,200.5 ns	1,207.6 ns	837,794.4	1.00	Yes	0.2728	2288 B	1.00
InlineSpanBasedSplitBenchmarkFeexed	.NET Framework 4.7.2	:tmi(...)TE\r\n [528]	1,762.9 ns	12.81 ns	11.99 ns	3.09 ns	1,747.3 ns	1,753.5 ns	1,762.1 ns	1,771.2 ns	1,785.4 ns	567,257.4	0.90	No	0.3967	2503 B	1.00
InlineSpanBasedSplitBenchmark	.NET Framework 4.7.2	:tmi(...)TE\r\n [528]	1,966.2 ns	7.10 ns	5.93 ns	1.64 ns	1,957.9 ns	1,960.5 ns	1,966.0 ns	1,971.2 ns	1,975.3 ns	508,596.9	1.00	Yes	0.3967	2503 B	1.00
InlineSpanBasedSplitBenchmarkFeexed	Mono Unity 2019.4.28f1	:tmi(...)TE\r\n [528]	4,857.3 ns	44.47 ns	39.42 ns	10.53 ns	4,814.6 ns	4,831.3 ns	4,841.6 ns	4,868.3 ns	4,944.2 ns	205,874.2	0.93	No	0.4883	-	NA
InlineSpanBasedSplitBenchmark	Mono Unity 2019.4.28f1	:tmi(...)TE\r\n [528]	5,232.8 ns	51.28 ns	45.46 ns	12.15 ns	5,187.0 ns	5,204.2 ns	5,215.4 ns	5,257.1 ns	5,327.6 ns	191,101.3	1.00	Yes	0.4883	-	NA
InlineSpanBasedSplitBenchmarkFeexed	Mono Unity 2021.2.0b4	:tmi(...)TE\r\n [528]	3,548.4 ns	21.69 ns	18.11 ns	5.02 ns	3,516.3 ns	3,537.9 ns	3,545.3 ns	3,559.5 ns	3,580.0 ns	281,816.6	0.92	No	0.4349	-	NA
InlineSpanBasedSplitBenchmark	Mono Unity 2021.2.0b4	:tmi(...)TE\r\n [528]	3,859.5 ns	34.08 ns	28.46 ns	7.89 ns	3,827.7 ns	3,840.5 ns	3,849.8 ns	3,867.4 ns	3,917.1 ns	259,101.4	1.00	Yes	0.4349	-	NA
InlineSpanBasedSplitBenchmarkFeexed	Mono Unity 2022.1.0a12	:tmi(...)TE\r\n [528]	3,471.6 ns	25.55 ns	23.90 ns	6.17 ns	3,443.7 ns	3,448.8 ns	3,472.1 ns	3,487.3 ns	3,519.8 ns	288,055.6	0.88	No	0.4349	-	NA
InlineSpanBasedSplitBenchmark	Mono Unity 2022.1.0a12	:tmi(...)TE\r\n [528]	3,922.2 ns	14.73 ns	12.30 ns	3.41 ns	3,905.0 ns	3,919.0 ns	3,920.5 ns	3,929.6 ns	3,948.7 ns	254,958.4	1.00	Yes	0.4349	-	NA