change to non optional utf8 function

[zunda-pixel]

String.data(using)? -> Data(String.utf8)
String(data:encoding)? -> String(decoding:as)

[allevato]

Could you measure the performance of these changes? I have a suspicion that the Data initializer taking a Sequence<UInt8> might be slower than the String method from Foundation (though I'd be happy to be wrong).

You should be able to use the recently added --measure-instructions flag before and after your change to get rough numbers to start.

[zunda-pixel]

I don't known how to use --measure-instructions.
is this swift test?

[zunda-pixel]

I found source code. but I don't known this code used in current Swift.

• swift-corelibs-foundation data(using:allowLossyConversion)
• swift-foundation data(using:allowLossyConversion)

[allevato]

I don't known how to use --measure-instructions. is this swift test?

It's a swift-format flag. Try running the following commands with and without your change and report the number of instructions in each case:

swift-format lint --measure-instructions Package.swift
swift-format format --measure-instructions Package.swift

[zunda-pixel]

result is unstable?

Name	Lint	Format
Data(String.utf8)	83694608	103411109
String.data(using: .utf8)	89545458	130931785