orElseThrow
private static <T> HttpMessageWriter<T> findWriter(
BodyInserter.Context context, ResolvableType elementType, @Nullable MediaType mediaType) {
return context.messageWriters().stream()
.filter(messageWriter -> messageWriter.canWrite(elementType, mediaType))
.findFirst()
.map(BodyInserters::<T>cast)
.orElseThrow(() -> new IllegalStateException(
"No HttpMessageWriter for "" + mediaType + "" and "" + elementType + """));
}