[Flight] FlightInfo should use signed integer types for payload size #21031
Description
The de-facto practice is to use -1 in FlightInfo to indicate that the number of records/size of the payload is unknown, looking at the Java implementation. However, the Protobuf definition uses an unsigned integer type, as does the C++ implementation.
Reporter: David Li / @lidavidm
Assignee: David Li / @lidavidm
PRs and other links:
Note: This issue was originally created as ARROW-4474. Please see the migration documentation for further details.