Add JavaDoc for ReactiveJdbcAdapter.getLock()

Author: Michael-A-McMahon

src/main/java/oracle/r2dbc/impl/ReactiveJdbcAdapter.java

@@ -534,6 +534,14 @@ Publisher<Void> publishClobWrite(
    */
   Publisher<Void> publishClobFree(Clob clob) throws R2dbcException;
 
+  /**
+   * Returns the {@link AsyncLock} that guards access to the JDBC
+   * {@link java.sql.Connection} created by this adapter (with
+   * {@link #publishConnection(DataSource, Executor)}). This lock may be
+   * acquired asynchronously, such that threads do not contend for the JDBC
+   * connection or any object created by that connection.
+   * @return Lock that guards access to the JDBC connection of this adapter.
+   */
   AsyncLock getLock();
 
   /**