[C++] Flatbuffers based serialization protocol for Expressions

[asfimport]

It might provide a more scalable solution for serialization.

cc @bkietz @fsaintjacques

Reporter: Krisztian Szucs / @kszucs

Related issues:

• [C++] C++ array kernels framework and execution buildout (umbrella issue) (relates to)

_{Note: This issue was originally created as ARROW-8214. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
We will need to create a serialization scheme for general array expressions (for use with arrow/compute)

[asfimport]

Micah Kornfield / @emkornfield:
When someone takes this up it would be nice if there was a discussion on how this will be unified with gandiva protobuf expression representation

[asfimport]

Wes McKinney / @wesm:
Yes, I would definitely like to see that happen. Using Flatbuffers is desirable to avoid the need to link libprotobuf.a

[asfimport]

Antoine Pitrou / @pitrou:
Shouldn't this be closed in favour of the compute IR-related JIRAs?

[asfimport]

Micah Kornfield / @emkornfield:
I think the IR model seems like the right way to go with this.

[asfimport]

Krisztian Szucs / @kszucs:
Yes, superseded by the IR proposal.