More extensions support

[steverao]

Higher Priority for extensions

• Support distinguishing between different instrumenters within the same instrumentation​.

• Current Status: Currently, customization decisions are based on the instrumentation name, which fails to distinguish between different instrumenters under the same instrumentation (e.g., armeria client and server).​ Related Support extensions for attributesExtractors, contextCustomizers, operationListeners and spanNameExtractor #13917

• Proposed Solution: Provide a dynamic check mechanism to expose the original span name and kind, Or we could use the span suppression keys (the ones that we get from the extractors) to expose what kind of instrumenter we are dealing with.

Medium priority for extensions

• Support modifying span kind​.
• Requirement: The current customization capabilities do not cover span kind modification. This customization scenario needs to be evaluated and supported.

[123liuziming]

I hope I can use my own TraceProvider more flexibly in the project.

JavaAgent will install its own OpenTelemetry SDK in io.opentelemetry.javaagent.tooling.OpenTelemetryInstaller#installOpenTelemetrySdk which uses AutoConfiguredOpenTelemetrySdkBuilder, but AutoConfiguredOpenTelemetrySdkBuilder can only customize the following components:

Users may need to customize the OpenTelemetry SDK in more detail, for example:

OpenTelemetrySdk.builder().setTracerProvider(new MyTraceProvider());

but unfortunately there is no such hook in installOpenTelemetrySdk. Perhaps we can provide a hook point in the installOpenTelemetrySdk to allow users to customize components such as TraceProvider, MeterProvider at a deeper level.