toNumber() function NOT returning a number

[#1]

When attempting to insert a timestamp in milliseconds into a flowfile using the UpdateRecord processor, the timestamp comes out expressed as a string (first image) despite the fact that I've explicitly cast it as a number (second image).   How can I get this expressed as a number like it is supposed to?

 

[#2 · Accepted solution]

I resorted to using an Avro schema with the RecordsetWriter in order to coerce the values into numbers.  So even though the documentation says toNumber's return type is "Number", it doesn't get expressed that way.  But the schema fixes it so its all good.