Grunet

I would be interested in working on this, but would probably need a little bit of direction (in particular into what the process should look like for bundling the binary)...

Yeah let me see if I can do this while tackling #703, since that seemed like they'd depend on the 2nd and 3rd bullet point Otherwise I'll try it out...

Yeah looking at it more closely it seems like it will probably deserve its own PR. I can still plan to give it a try though

@tidal it looks like what's currently living in AbstractSpan at the moment almost exactly mirrors what's [in Java's version](https://github.com/open-telemetry/opentelemetry-java/blame/main/api/all/src/main/java/io/opentelemetry/api/trace/Span.java#L35) ([this PR](https://github.com/open-telemetry/opentelemetry-java/pull/1843) and [this other PR](https://github.com/open-telemetry/opentelemetry-java/issues/1807) seem to have some discussion...

Yeah that all seems reasonable to me. @brettmc @Nevay does @tidal's reasoning above seem appropriate to you to deviate from the Java implementation's patterns? If so, I can go ahead...

I'm guessing this one doesn't need to be thought out from scratch too much, and just following along with another language's implementation (or 2) with the spec at hand will...

Am a little personally underwater atm (ideally will not be in ~2-3 weeks) but once not was planning to take a stab at #723 first. But if this is a...

Looking at it more closely now, I have 2 other observations 1) [JS](https://github.com/open-telemetry/opentelemetry-js/blob/f59c5b268bd60778d7a0d185a6044688f9e3dd51/packages/opentelemetry-shim-opentracing/src/shim.ts) and [Python](https://github.com/open-telemetry/opentelemetry-python/blob/71e3a7a192c0fc8a7503fac967ada36a74b79e58/shim/opentelemetry-opentracing-shim/src/opentelemetry/shim/opentracing_shim/__init__.py) keep all of the Shim classes in a single file, but [Java](https://github.com/open-telemetry/opentelemetry-java/tree/50408d499f85d5761d0a5ed9bf9d77d5ff01fff5/opentracing-shim/src/main/java/io/opentelemetry/opentracingshim) separates them out...

So there are a total of 27 methods across 5 interfaces that you need to fill out to make any OpenTracing-PHP implementation (including an OTEL-backed one as is needed here)...

New to this repo, but I feel like I've noticed some of 2-6 as well recently. Not being too familiar with things, I'd be curious how many decisions for things...