Support for optional fields in proto3?

[dcj]

While attempting to protoc compile a bunch of .proto files, several times I encountered this message:

foo.proto is a proto3 file that contains optional fields, 
but code generator protoc-gen-clojure hasn't been updated to support optional fields in proto3. 
Please ask the owner of this code generator to support proto3 optional.

What is the prognosis/timeline for this, if any?
If not, any idea how much work it would be for someone who knows almost nothing about protobufs to add this?