API clean up

driver/src/main/java/org/neo4j/driver/internal/reactive/InternalRxSession.java

@@ -98,30 +98,30 @@ private Publisher<RxTransaction> beginTransaction( AccessMode mode, TransactionC
     }
 
     @Override
-    public <T> Publisher<T> readTransaction( RxTransactionWork<Publisher<T>> work )
+    public <T> Publisher<T> readTransaction( RxTransactionWork<? extends Publisher<T>> work )
     {
         return readTransaction( work, TransactionConfig.empty() );
     }
 
     @Override
-    public <T> Publisher<T> readTransaction( RxTransactionWork<Publisher<T>> work, TransactionConfig config )
+    public <T> Publisher<T> readTransaction( RxTransactionWork<? extends Publisher<T>> work, TransactionConfig config )
     {
         return runTransaction( AccessMode.READ, work, config );
     }
 
     @Override
-    public <T> Publisher<T> writeTransaction( RxTransactionWork<Publisher<T>> work )
+    public <T> Publisher<T> writeTransaction( RxTransactionWork<? extends Publisher<T>> work )
     {
         return writeTransaction( work, TransactionConfig.empty() );
     }
 
     @Override
-    public <T> Publisher<T> writeTransaction( RxTransactionWork<Publisher<T>> work, TransactionConfig config )
+    public <T> Publisher<T> writeTransaction( RxTransactionWork<? extends Publisher<T>> work, TransactionConfig config )
     {
         return runTransaction( AccessMode.WRITE, work, config );
     }
 
-    private <T> Publisher<T> runTransaction( AccessMode mode, RxTransactionWork<Publisher<T>> work, TransactionConfig config )
+    private <T> Publisher<T> runTransaction( AccessMode mode, RxTransactionWork<? extends Publisher<T>> work, TransactionConfig config )
     {
         Flux<T> repeatableWork = Flux.usingWhen( beginTransaction( mode, config ), work::execute,
                 RxTransaction::commit, ( tx, error ) -> tx.rollback(), null );

driver/src/main/java/org/neo4j/driver/reactive/RxSession.java

@@ -83,7 +83,7 @@ public interface RxSession extends RxStatementRunner
      * publisher can be completed exceptionally if given work or commit fails.
      *
      */
-    <T> Publisher<T> readTransaction( RxTransactionWork<Publisher<T>> work );
+    <T> Publisher<T> readTransaction( RxTransactionWork<? extends Publisher<T>> work );
 
     /**
      * Execute given unit of reactive work in a {@link AccessMode#READ read} reactive transaction with
@@ -106,7 +106,7 @@ public interface RxSession extends RxStatementRunner
      * publisher can be completed exceptionally if given work or commit fails.
      *
      */
-    <T> Publisher<T> readTransaction( RxTransactionWork<Publisher<T>> work, TransactionConfig config );
+    <T> Publisher<T> readTransaction( RxTransactionWork<? extends Publisher<T>> work, TransactionConfig config );
 
     /**
      * Execute given unit of reactive work in a {@link AccessMode#WRITE write} reactive transaction.
@@ -127,7 +127,7 @@ public interface RxSession extends RxStatementRunner
      * publisher can be completed exceptionally if given work or commit fails.
      *
      */
-    <T> Publisher<T> writeTransaction( RxTransactionWork<Publisher<T>> work );
+    <T> Publisher<T> writeTransaction( RxTransactionWork<? extends Publisher<T>> work );
 
     /**
      * Execute given unit of reactive work in a {@link AccessMode#WRITE write} reactive transaction with
@@ -150,7 +150,7 @@ public interface RxSession extends RxStatementRunner
      * publisher can be completed exceptionally if given work or commit fails.
      *
      */
-    <T> Publisher<T> writeTransaction( RxTransactionWork<Publisher<T>> work, TransactionConfig config );
+    <T> Publisher<T> writeTransaction( RxTransactionWork<? extends Publisher<T>> work, TransactionConfig config );
 
     /**
      * Run a statement with parameters in an auto-commit transaction with specified {@link TransactionConfig} and return a reactive result stream.