pixelflut: Ignore EAGAIN errors

Very contested servers are likely to cause EAGAIN socket errors on the
client. Since these errors are not supposed to be fatal, just try
sending the pixel again.

This was tested successfully against massively contested 37c3 pixelflut
servers.

Userland/Utilities/pixelflut.cpp

@@ -118,7 +118,12 @@ ErrorOr<void> Client::send_current_pixel()
     auto hex_without_hash = hex.substring(1);
 
     // PX <x> <y> <hex color>
-    TRY(m_socket->write_formatted("PX {} {} {}\n", m_current_point.x() + m_image_offset.x(), m_current_point.y() + m_image_offset.y(), hex_without_hash));
+    while (true) {
+        auto result = m_socket->write_formatted("PX {} {} {}\n", m_current_point.x() + m_image_offset.x(), m_current_point.y() + m_image_offset.y(), hex_without_hash);
+        // Very contested servers will cause frequent EAGAIN errors.
+        if (!result.is_error() || result.error().code() != EAGAIN)
+            break;
+    }
     return {};
 }