Feat/native 4byte tracer

[natebeauregard]

Changes

• Sets up infrastructure to create and register custom native tracers
• Adds a native 4byte tracer implementation
  • The 4byteTracer collects the function selectors of every function executed in the lifetime of a transaction, along with the size of the supplied call data. The result is a dictionary where the keys are SELECTOR-CALLDATASIZE and the values are number of occurrences of this key.
• Renames the 4byte tracer JS implementation to be 4byteTracer_legacy

Types of changes

What types of changes does your code introduce?

• Bugfix (a non-breaking change that fixes an issue)
• New feature (a non-breaking change that adds functionality)
• Breaking change (a change that causes existing functionality not to work as expected)
• Optimization
• Refactoring
• Documentation update
• Build-related changes
• Other: Description

Testing

Requires testing

• Yes
• No

If yes, did you write tests?

• Yes
• No

Notes on testing

I repurposed a script that @Marchhilloriginally wrote for automating testing the JS tracer implementations. The script listens for new blocks/transactions, sends a request to get the 4byteTracer results, and compares the native and legacy tracer results and checks for any differences.

We'll also want to do some performance testing to ensure that the performance is significantly better than the JS implementation and comparable to Geth/Reth.

Documentation

Requires documentation update

• Yes
• No

Requires explanation in Release Notes

• Yes
• No

[LukaszRozmej]

Overall very good, just few nitpicks and potential ideas to consider.

[LukaszRozmej]

micro-optimization: you could use string.create instead of concatenating strings, resulting in less allocations.

[natebeauregard]

I attempted to follow the approach used to create strings in StateTestTxTracer, however I've been having some difficulty trying to implement it correctly. I may reach out for some assistance if I can't figure it out

[LukaszRozmej]

Not sure if worth it as it makes it less readable:

        static int GetDigitsBase10(int n) => n == 0 ? 1 : (int)Math.Floor(Math.Log10(Math.Abs(n)) + 1);
        const int length = 4;
        string _4byteId = string.Create(length * 2 + 1 + GetDigitsBase10(size), (input, size), (span, state) =>
        {
            ref char charsRef = ref MemoryMarshal.GetReference(span);
            ReadOnlySpan<byte> bytes = state.input.Span[..length];
            Bytes.OutputBytesToCharHex(ref MemoryMarshal.GetReference(bytes), length, ref charsRef, false, 0);
            span[length * 2] = '-';
            size.TryFormat(span.Slice(length * 2 + 1), out _);
        });

[natebeauregard]

Oh cool! Since the main goal of this PR is to optimize performance for the tracers then I think it makes sense to use this, even if it's less readable. I'll add a comment explaining that it's just concatenating strings

[Marchhill]

Just a few small nitpicks, looks good as long as the script isn't finding any diffs

[Marchhill]

nitpick: public variable starting with _

[natebeauregard]

Yeah I wasn't sure what to do here since the variable name starts with a number. Should I just rename the constant to be FourByteTracer instead?