LightStep::ScopeManager interface differs from OpenTracing::ScopeManager

[mkasberg]

In OpenTracing::ScopeManager, the span parameter is a required arg, not a keyword arg.

def activate(span, finish_on_close: true)

https://github.com/opentracing/opentracing-ruby/blob/01304d46b6d8322e23bb2962189c0cd14065c886/lib/opentracing/scope_manager.rb#L21

However, in LightStep::ScopeManager, the span parameter is a keyword arg.

lightstep-tracer-ruby/lib/lightstep/scope_manager.rb

Line 19 in cbfb22e

def activate(span:, finish_on_close: true)

This makes LightStep::ScopeManager incompatible with the interface defined in OpenTracing::ScopeManager. For example, this error is thrown if you call activate as defined in the OpenTracing interface.

wrong number of arguments (given 1, expected 0; required keyword: span)