OkHttp: flush early

git-svn-id: https://svn.apache.org/repos/asf/chemistry/opencmis/trunk@1753466 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/chemistry-opencmis-client/chemistry-opencmis-client-bindings/src/main/java/org/apache/chemistry/opencmis/client/bindings/spi/http/OkHttpHttpInvoker.java b/chemistry-opencmis-client/chemistry-opencmis-client-bindings/src/main/java/org/apache/chemistry/opencmis/client/bindings/spi/http/OkHttpHttpInvoker.java
index 91de63d..a7f8ae9 100644
--- a/chemistry-opencmis-client/chemistry-opencmis-client-bindings/src/main/java/org/apache/chemistry/opencmis/client/bindings/spi/http/OkHttpHttpInvoker.java
+++ b/chemistry-opencmis-client/chemistry-opencmis-client-bindings/src/main/java/org/apache/chemistry/opencmis/client/bindings/spi/http/OkHttpHttpInvoker.java
@@ -22,6 +22,7 @@
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.OutputStream;
 import java.math.BigInteger;
 import java.util.List;
 import java.util.Map;
@@ -120,7 +121,9 @@
                     @Override
                     public void writeTo(BufferedSink sink) throws IOException {
                         try {
-                            writer.write(sink.outputStream());
+                            OutputStream out = sink.outputStream();
+                            writer.write(out);
+                            out.flush();
                         } catch (IOException ioe) {
                             throw ioe;
                         } catch (Exception e) {