fix FasterXML#155: Only flush outputs when FLUSH_PASSED_TO_STREAM is allowed

Previously most serializers would attempt a flush when
AUTO_CLOSE_TARGET was disabled, which is not expected if
FLUSH_PASSED_TO_STREAM is also disabled.

This change results in binary serializers behaving the same as
the json serializer.

Author: carterkozak

avro/src/main/java/com/fasterxml/jackson/dataformat/avro/AvroGenerator.java

@@ -292,7 +292,9 @@ public final void writeStringField(String fieldName, String value)
 
     @Override
     public final void flush() throws IOException {
-        _output.flush();
+        if (isEnabled(StreamWriteFeature.FLUSH_PASSED_TO_STREAM)) {
+            _output.flush();
+        }
     }
 
     @Override

cbor/src/main/java/com/fasterxml/jackson/dataformat/cbor/CBORGenerator.java

@@ -1128,7 +1128,7 @@ && isEnabled(StreamWriteFeature.AUTO_CLOSE_CONTENT)) {
         if (_ioContext.isResourceManaged()
                 || isEnabled(StreamWriteFeature.AUTO_CLOSE_TARGET)) {
             _out.close();
-        } else {
+        } else if (isEnabled(StreamWriteFeature.FLUSH_PASSED_TO_STREAM)) {
             // If we can't close it, we should at least flush
             _out.flush();
         }

protobuf/src/main/java/com/fasterxml/jackson/dataformat/protobuf/ProtobufGenerator.java

@@ -326,7 +326,9 @@ public final void flush() throws IOException
                 _output.write(_currBuffer, start, len);
             }
         }
-        _output.flush();
+        if (isEnabled(StreamWriteFeature.FLUSH_PASSED_TO_STREAM)) {
+            _output.flush();
+        }
     }
 
     @Override

smile/src/main/java/com/fasterxml/jackson/dataformat/smile/SmileGenerator.java

@@ -1807,7 +1807,7 @@ && isEnabled(StreamWriteFeature.AUTO_CLOSE_CONTENT)) {
 
         if (_ioContext.isResourceManaged() || isEnabled(StreamWriteFeature.AUTO_CLOSE_TARGET)) {
             _out.close();
-        } else {
+        } else if (isEnabled(StreamWriteFeature.FLUSH_PASSED_TO_STREAM)) {
             // If we can't close it, we should at least flush
             _out.flush();
         }