feat(instrumentation): make InstrumentationAbstract.init public (#4418)

* Make InstrumentationAbstract.init public

* Update changelog

* Update JSDoc

---------

Co-authored-by: Marc Pichler <[email protected]>

Author: drewcorlin1

CHANGELOG.md

@@ -11,6 +11,8 @@ For experimental package changes, see the [experimental CHANGELOG](experimental/
 
 ### :rocket: (Enhancement)
 
+* feat(instrumentation): Make `init()` method public [#4418](https://github.com/open-telemetry/opentelemetry-js/pull/4418)
+
 ### :bug: (Bug Fix)
 
 ### :books: (Refine Doc)

experimental/CHANGELOG.md

@@ -8,6 +8,7 @@ All notable changes to experimental packages in this project will be documented
 
 ### :rocket: (Enhancement)
 
+* feat(instrumentation): Make `init()` method public [#4418](https://github.com/open-telemetry/opentelemetry-js/pull/4418)
 * feat(exporter-metrics-otlp-http): add option to set the exporter aggregation preference  [#4409](https://github.com/open-telemetry/opentelemetry-js/pull/4409) @AkselAllas
 * feat(node-sdk): add spanProcessors option [#4454](https://github.com/open-telemetry/opentelemetry-js/pull/4454) @naseemkullah
 

experimental/packages/opentelemetry-instrumentation/src/instrumentation.ts

@@ -134,9 +134,12 @@ export abstract class InstrumentationAbstract<T = any>
 
   /**
    * Init method in which plugin should define _modules and patches for
-   * methods
+   * methods.
+   * Use `enable()` if you are trying to turn on this plugin. This method
+   * will return objects to patch specific modules with the appropriate
+   * instrumentation (or not return anything).
    */
-  protected abstract init():
+  abstract init():
     | InstrumentationModuleDefinition<T>
     | InstrumentationModuleDefinition<T>[]
     | void;