Instrument "box" naming

[ktoso]

(ignoring how the inject/extract to/from are expressed).

We'd want to write Instrument as the generic rather than I since that's common swift style to use full words.
But we today use Instrument for the wrapper type:

    init<Instrument>(instrument: Instrument)
        where Instrument: InstrumentProtocol,
        Instrument.InjectInto == HTTPHeaders,
        Instrument.ExtractFrom == HTTPHeaders {

        self.instrument = Instrument(instrument) // conflict

What would be a better naming strategy for this type:

/// A box-type for an `InstrumentProtocol`, necessary for creating homogeneous collections of `InstrumentProtocol`s.
public struct Instrument<InjectInto, ExtractFrom>: InstrumentProtocol {
    private let inject: (BaggageContext, inout InjectInto) -> Void
    private let extract: (ExtractFrom, inout BaggageContext) -> Void

    /// Wrap the given `InstrumentProtocol` inside an `Instrument`.
    /// - Parameter instrument: The `InstrumentProtocol` being wrapped.
    public init<I>(_ instrument: I)
        where
        I: InstrumentProtocol,
        I.InjectInto == InjectInto,
        I.ExtractFrom == ExtractFrom {

TracingInstrument does come to mind, but these ones are not specifically tracing, they are generic.

Having looked at this again I guess this should be AnyInstrument and the protocol can become InstrumentProtocol (OR BaggageInstrument)... WDYT?

[slashmo]

Having looked at this again I guess this should be AnyInstrument and the protocol can become InstrumentProtocol

Agreed. Calling the generic type argument I felt like a necessary workaround rather than a good solution. I think AnyInstrument more clearly communicates the intent 👍 I'd prefer Instrument for the protocol, but then we'd have to use I or something similar again, so I guess calling it InstrumentProtocol is worth the trade-off.

[ktoso]

Yeah, sounds like reasonable tradeoffs 👍