separate out instrument_connection() in aiopg doc strings

Author: beijiez

instrumentation/opentelemetry-instrumentation-aiopg/src/opentelemetry/instrumentation/aiopg/__init__.py

@@ -25,7 +25,7 @@
 
     import aiopg
     from opentelemetry.instrumentation.aiopg import AiopgInstrumentor
-
+    # Call instrument() to wrap all database connections
     AiopgInstrumentor().instrument()
 
     cnx = await aiopg.connect(database='Database')
@@ -42,11 +42,18 @@
     cursor.close()
     cnx.close()
 
-    cnx = AiopgInstrumentor().instrument_connection(cnx)
-    cursor = await cnx.cursor()
+.. code-block:: python
+
+    import aiopg
+    from opentelemetry.instrumentation.aiopg import AiopgInstrumentor
+
+    # Alternatively, use instrument_connection for an individual connection
+    cnx = await aiopg.connect(database='Database')
+    instrumented_cnx = AiopgInstrumentor().instrument_connection(cnx)
+    cursor = await instrumented_cnx.cursor()
     await cursor.execute("INSERT INTO test (testField) VALUES (123)")
     cursor.close()
-    cnx.close()
+    instrumented_cnx.close()
 
 API
 ---