Update README.md (#2217)

README.md

@@ -301,6 +301,14 @@ and you want to suppress some of them without modifying the code.
 | trace.annotated.methods.exclude | TRACE_ANNOTATED_METHODS_EXCLUDE | Suppress `@WithSpan` instrumentation for specific methods.
 Format is "my.package.MyClass1[method1,method2];my.package.MyClass2[method3]" |
 
+#### Creating spans around methods with otel.instrumentation.methods.include
+This is a way to to create a span around a first-party code method without using `@WithSpan`.
+
+| System property | Environment variable | Purpose |
+|---------------------------------|---------------------------------|------------------------------------------------------------------------------------------------------------------------------------------|
+| otel.instrumentation.methods.include | | Add instrumentation for specific methods in lieu of `@WithSpan`.
+Format is "my.package.MyClass1[method1,method2];my.package.MyClass2[method3]" |
+
 ### Creating spans manually with a Tracer
 
 OpenTelemetry offers a tracer to easily enable custom instrumentation throughout your application.