Add more logs for writing failures.

Bug: 62429763
Test: libappfuse_test
Change-Id: Ie0eabd09ae9ad3f8ba8c4f38f871dad16b5c58ff
diff --git a/libappfuse/FuseBuffer.cc b/libappfuse/FuseBuffer.cc
index 653e96b..1b47e0a 100644
--- a/libappfuse/FuseBuffer.cc
+++ b/libappfuse/FuseBuffer.cc
@@ -115,7 +115,10 @@
                 case EAGAIN:
                     return ResultOrAgain::kAgain;
                 default:
-                    PLOG(ERROR) << "Failed to write a FUSE message";
+                    PLOG(ERROR) << "Failed to write a FUSE message: "
+                                << "fd=" << fd << " "
+                                << "sockflag=" << sockflag << " "
+                                << "data=" << data;
                     return ResultOrAgain::kFailure;
             }
         }