This is a critical patch release.

It fixes various problems with producer.Spooling that prevented it from working at all. The issues were most likely introduced during the transition from 0.4.x to 0.5.x.

This version has been built with go 1.12.3

Fixed with 0.5.4

• producer.spooling is now functional again as messages were not written correctly since 0.5.0 (#248).
• producer.spooling now does not block upon shutdown (#248).
• metadata is now handled correctly when messages are sent to fallback (#247).
• producer.socket now sends messages directly to fallback if connect fails.