The SBE3 protocol is based on the Simple Binary Encoding (here). You can either use the API package OR write directly to the SBE schema and documentation to produce your own high-speed implementation.
The SBE3 API does not currently support RFQ/RFS flows. Only the 3.14.0 APIs and the upcoming Whisperer Direct support this feature. This version is good for market data and simple taker execution.
Further detail is provided in the following page(s):
Overview
Content Tools