libuv: stream try_write

src/libuv/Pipe.zig

@@ -127,6 +127,13 @@ test "Pipe" {
     // Check our data
     try testing.expectEqual(@as(usize, 5), data.data.items.len);
     try testing.expectEqualStrings("hello", data.data.items);
+    data.data.clearRetainingCapacity();
+
+    // Try writing directly
+    _ = try writer.tryWrite(&[_][]const u8{"world"});
+    _ = try loop.run(.once);
+    try testing.expectEqual(@as(usize, 5), data.data.items.len);
+    try testing.expectEqualStrings("world", data.data.items);
 
     // End
     reader.readStop();

src/libuv/stream.zig

@@ -63,6 +63,18 @@ pub fn Stream(comptime T: type) type {
             ));
         }
 
+        /// Same as uv_write(), but won’t queue a write request if it can’t
+        /// be completed immediately.
+        pub fn tryWrite(self: T, bufs: []const []const u8) !usize {
+            const res = c.uv_try_write(
+                @ptrCast(*c.uv_stream_t, self.handle),
+                @ptrCast([*c]const c.uv_buf_t, bufs.ptr),
+                @intCast(c_uint, bufs.len),
+            );
+            try errors.convertError(res);
+            return @intCast(usize, res);
+        }
+
         /// Read data from an incoming stream. The uv_read_cb callback will
         /// be made several times until there is no more data to read or
         /// uv_read_stop() is called.