Don't try to call read, if len i 0.

runtime/bin/socket_patch.dart

Index: runtime/bin/socket_patch.dart
diff --git a/runtime/bin/socket_patch.dart b/runtime/bin/socket_patch.dart
index 76289c505c7cf4e47e6f93479a3ed85dffa20d4f..27329f139abece776673f92b4604f1e6b353c515 100644
--- a/runtime/bin/socket_patch.dart
+++ b/runtime/bin/socket_patch.dart
@@ -449,7 +449,9 @@ class _NativeSocket extends NativeFieldWrapperClass1 {
       throw new ArgumentError("Illegal length $len");
     }
     if (isClosing || isClosed) return null;
-    var result = nativeRead(min(available, len == null ? available : len));
+    len = min(available, len == null ? available : len);
+    if (len == 0) return null;
+    var result = nativeRead(len);
     if (result is OSError) {
       reportError(result, "Read failed");
       return null;