Disable buffering for files created with ev/to-file

src/core/ev.c

@@ -3312,6 +3312,9 @@ static JanetFile *get_file_for_stream(JanetStream *stream) {
         /* _close(fd); */
         return NULL;
     }
+    if (setvbuf(f, NULL, _IONBF, 0)) {
+        return NULL;
+    }
 #else
     int newHandle = dup(stream->handle);
     if (newHandle < 0) return NULL;
@@ -3320,6 +3323,10 @@ static JanetFile *get_file_for_stream(JanetStream *stream) {
         close(newHandle);
         return NULL;
     }
+    if (setvbuf(f, NULL, _IONBF, 0)) {
+        close(newHandle);
+        return NULL;
+    }
 #endif
     return janet_makejfile(f, flags);
 }
@@ -3327,7 +3334,8 @@ static JanetFile *get_file_for_stream(JanetStream *stream) {
 JANET_CORE_FN(janet_cfun_to_file,
               "(ev/to-file)",
               "Create core/file copy of the stream. This value can be used "
-              "when blocking IO behavior is needed.") {
+              "when blocking IO behavior is needed. Buffering is turned off "
+              "for the file.") {
     janet_fixarity(argc, 1);
     JanetStream *stream = janet_getabstract(argv, 0, &janet_stream_type);
     JanetFile *iof = get_file_for_stream(stream);

test/suite-ev.janet

@@ -422,7 +422,6 @@
 (expect-read bob "Whats your name?\n")
 (def fbob (ev/to-file bob))
 (file/write fbob "bob")
-(file/flush fbob)
 (:close fbob)
 (expect-read bob "Welcome bob\n")
 (def alice (net/connect test-host test-port))