Adds or replaces the seed for a message id.
Adds a message by its definition, deriving the seed, and returns it.
This is the whole path for a vendor dialect: describe the message once, and every frame carrying it checks from then on.
Returns the seed this dialect resolves a message id to, or null if neither it nor the common dialect knows the id.
The
CRC_EXTRAseeds of a dialect beyond the common one.Entries added here are consulted before the built-in common-dialect registry, so a private dialect may also override an id the common one defines.