[geary/mjog/692-dont-serialise-empty-array] Geary.Imap.Serializer: Don't try to serialise empty literal data

[Michael Gratton <mjog src gnome org>]

commit 97530fac96a96fc320ce7ed9843c48b2d3e80aa2
Author: Michael Gratton <mike vee net>
Date:   Fri Mar 20 20:07:29 2020 +1100

    Geary.Imap.Serializer: Don't try to serialise empty literal data
    
    Fixes #692

 src/engine/imap/transport/imap-serializer.vala | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)
---
diff --git a/src/engine/imap/transport/imap-serializer.vala b/src/engine/imap/transport/imap-serializer.vala
index 36dafca9..549391fc 100644
--- a/src/engine/imap/transport/imap-serializer.vala
+++ b/src/engine/imap/transport/imap-serializer.vala
@@ -106,12 +106,14 @@ public class Geary.Imap.Serializer : BaseObject {
     public async void push_literal_data(uint8[] buffer,
                                         GLib.Cancellable? cancellable = null)
         throws GLib.Error {
-        yield this.output.write_all_async(
-            buffer,
-            Priority.DEFAULT,
-            cancellable,
-            null
-        );
+        if (buffer.length > 0) {
+            yield this.output.write_all_async(
+                buffer,
+                Priority.DEFAULT,
+                cancellable,
+                null
+            );
+        }
     }
 
     /**