[Feature Request] forEachBaggageItems on SpanContext

[meteorlxy]

Implementations of many other languages have something like forEachBaggageItems on SpanContext:

• go: https://github.com/opentracing/opentracing-go/blob/master/span.go#L21
• java: https://github.com/opentracing/opentracing-java/blob/2df2a8983e35dff23c4fb894e5f5ae3f98f1cf7b/opentracing-api/src/main/java/io/opentracing/SpanContext.java#L59
• cpp: https://github.com/opentracing/opentracing-cpp/blob/7b8c0b30a26b138dbed714cde8347a0f5f2e060e/include/opentracing/span.h#L27

However, js does not:

opentracing-javascript/src/span_context.ts

Lines 11 to 33 in cb74683

	export class SpanContext {
	// The SpanContext is entirely implementation dependent
	/**
	* Returns a string representation of the implementation internal trace ID.
	*
	* @returns {string}
	*/
	toTraceId(): string {
	return '';
	}
	/**
	* Returns a string representation of the implementation internal span ID.
	*
	* @returns {string}
	*/
	toSpanId(): string {
	return '';
	}
	}
	export default SpanContext;