Update fn_async for Fetch Result Method 4:

Advantages
Means single message (that fits in arma extension limit) only 1
callExtension Required (was 2 previous)

Disadvantages
extDB required version now v19+
Multi-message Results now requires..
Number of callExtensions to fit Result + 2 extra callExtensions.
One callExtension to get [5], another callExtension with "" to signal
end of Result.

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Most / All Altis Life standard Database callExtension fit in a single
message.
Considering it was broken for awhile with the format code (8k Limit)
Arma 3 callExtension limit last i checked was 10k.