After entering name in the box, it was showing a red message below it rather than greeting properly(I am unable to show that screenshot as I have resolved the bug)
dest := (*[1024]byte)(unsafe.Pointer(uintptr(ptr)))
copy(dest[:size], dataBytes)
(above block code of code was causing error if JSON response exceeds 1024 bytes)
Fix: After entering the name, it should greet instead of giving error.