Use MemoryExtensions.Split over string.Split to decrease allocations/improve perf

[h3xds1nz]

Description

Picks off most places where string.Split is used just for parts count or where additional operations are performed on the split strings so it makes sense to work with ReadOnlySpan<char>/SpanSplitEnumerator<char> instead.

Using string.Split vs SpanSplitEnumerator<char> for counting

Method	updatedFilter	Mean [ns]	Error [ns]	StdDev [ns]	Gen0	Code Size [B]	Allocated [B]
Original	Image(...))|*.* [68]	49.09 ns	0.676 ns	0.600 ns	0.0172	672 B	288 B
PR__EDIT	Image(...))|*.* [68]	17.23 ns	0.075 ns	0.066 ns	-	412 B	-

Benchmark code

[Benchmark]
[Arguments("Image Files(*.BMP;*.JPG;*.GIF)|*.BMP;*.JPG;*.GIF|All files (*.*)|*.*")]
public  int Original(string updatedFilter)
{
    string[] formats = updatedFilter.Split('|');

    return formats.Length; 
}

[Benchmark]
[Arguments("Image Files(*.BMP;*.JPG;*.GIF)|*.BMP;*.JPG;*.GIF|All files (*.*)|*.*")]
public int PR__EDIT(string updatedFilter)
{
    int formatsCount = 0;
    foreach (Range range in updatedFilter.AsSpan().Split('|'))
        formatsCount++;

    return formatsCount;
}

Customer Impact

Improved performance, decreased allocations.

Regression

No.

Testing

Local build/CI.

Risk

Low.

Microsoft Reviewers: Open in CodeFlow

[harshit7962]

LGTM.

@h3xds1nz, Found the additional assignments of Range[] a very interesting way to discard or deal with unwanted and extra splits. Enjoyed reviewing this!

Can you please resolve conflicts and this is good to be taken in.

[h3xds1nz]

@harshit7962 Thank you, glad you've enjoyed it! Resolved the conflicts :)

[harshit7962]

Re-Approving

[harshit7962]

@h3xds1nz Thanks again for the contribution!

[h3xds1nz]

@harshit7962 Thanks again for reviewing :)

[h3xds1nz]

@harshit7962 you didn't squash by the way, all my ugly commit messages out in the main branch now haha.