// https://github.com/golang/go/blob/d6f2f833c93a41ec1c68e49804b8387a06b131c5/src/runtime/traceback.go#L347-L368
	pcs []uintptr

	// firstPCFrames and firstPCSymbolizeResult hold the results of the
	// allFrames call for the first (leaf-most) PC this locInfo represents
	firstPCFrames          []runtime.Frame
	firstPCSymbolizeResult symbolizeFlag
}

// newProfileBuilder returns a new profileBuilder.