SSR correction multiple message flag also set

[ourairquality]

Tried using the https://ntrip.data.gnss.ga.gov.au/SSRA00GAA0 service as described https://geoscienceaustralia.github.io/ginan/resources/GA-STREAMdatasheet20220615v01.pdf and using RTKLIB as the client, and tried to track down why the RTCM3 SSR messages are not processed beyond decoding, and it appears that the MMI bit in the SSR headers is always set, that there is never a messages sent with the MMI bit clear to indicate the last message which RTKLIB uses to trigger further processing.

This service claims to run Ginan, and at a guess might the relevant code be NtripUploader::messageTimeout_handler() ssrMeta.multipleMessage = 1; // We assume there will be more messages. and might the logic to clear this flag when sending the last message have an issue.

Btw the datasheet above does not mention the 'Global/regional CRS indicator' bit in the header for the 1060 message, yet Ginan appears to encode and decode that, so might that datasheet be in error.