Binary data exchange format (BSON, protobuf wire format)

I’ve been wondering if there’s a way to send/receive data to/from AppSync API in binary format, such as BSON or protobuf, instead of JSON text format. This helps us effortlessly avoid payload limits by AppSync and Lambda as the data source. Thanks.

No repository files or tests are named. Start by reviewing AppSync API and Lambda payload-limit documentation, then determine whether BSON or protobuf wire-format request and response exchange is supported. Done means the feasibility, constraints, and a concrete next step are documented.

Written by the indexing model from the issue text.