[Networking] Use string concatenation in tracers\

[peterargue]

Problem Definition

I was reviewing a profile from an Access node and noticed that 1% of CPU on the node was used by fmt.Sprintf generating the ID for RPC tracer cache entries.

While this isn't a huge problem, the fix is very simple so we may as well make it.

Proposed Solution

Update the following code:

flow-go/network/p2p/tracer/internal/rpc_sent_cache.go

Line 82 in ad12394

return flow.MakeIDFromFingerPrint([]byte(fmt.Sprintf("%s%s", messageId, controlMsgType)))

to use

flow.MakeIDFromFingerPrint([]byte(messageId + string(controlMsgType)))