File upload performance improvement

[loyldg]

When uploading files, too much memory is allocated. We can use MemoryPool<byte> to reduce memory allocation and improve performance.

Below is the performance comparison before and after optimization.

MinioClient.ReadFullAsync

.NET SDK 9.0.302
[Host] : .NET 9.0.7 (9.0.725.31616), X64 RyuJIT AVX-512F+CD+BW+DQ+VL
.NET 9.0 : .NET 9.0.7 (9.0.725.31616), X64 RyuJIT AVX-512F+CD+BW+DQ+VL

Job=.NET 9.0 Runtime=.NET 9.0

Method	Size	Mean	Error	StdDev	Ratio	RatioSD	Gen0	Gen1	Gen2	Allocated	Alloc Ratio
ReadFullAsync	65536	4.532 μs	0.0585 μs	0.0488 μs	1.00	0.01	3.7994	-	-	65816 B	1.000
ReadFullAsync_New	65536	1.495 μs	0.0069 μs	0.0077 μs	0.33	0.00	0.0153	-	-	264 B	0.004
ReadFullAsync	1048576	52.505 μs	0.2932 μs	0.2599 μs	1.00	0.01	333.3130	333.3130	333.3130	1049064 B	1.000
ReadFullAsync_New	1048576	1.600 μs	0.0151 μs	0.0142 μs	0.03	0.00	0.0153	-	-	264 B	0.000
ReadFullAsync	16777216	477.361 μs	9.5429 μs	11.7195 μs	1.001	0.03	666.0156	666.0156	666.0156	16777923 B	1.000
ReadFullAsync_New	16777216	1.504 μs	0.0158 μs	0.0147 μs	0.003	0.00	0.0153	-	-	264 B	0.000

S3utils.IsAmazonEndPoint

.NET SDK 9.0.302
[Host] : .NET 9.0.7 (9.0.725.31616), X64 RyuJIT AVX-512F+CD+BW+DQ+VL
.NET 9.0 : .NET 9.0.7 (9.0.725.31616), X64 RyuJIT AVX-512F+CD+BW+DQ+VL

Job=.NET 9.0 Runtime=.NET 9.0

Method	Mean	Error	StdDev	Ratio	Rank	Gen0	Allocated	Alloc Ratio
IsAmazonEndPoint	4,762.6 ns	39.81 ns	33.24 ns	1.00	2	0.3204	5584 B	1.00
IsAmazonEndPoint_New	655.3 ns	1.13 ns	1.05 ns	0.14	1	-	-	0.00