The current libmongocrypt API requires the driver to pass the local schema for each operation with mongocrypt_ctx_setopt_schema. This requires the driver to determine the namespace of a command. To simplify the integration, let's have the driver set the schema_map once, as a BSON object mapping namespaces to schemas, in a new API function:

bool mongocrypt_setopt_local_schema_map (mongocrypt_t *crypt, mongocrypt_binary_t *schema_map)

And let's remove mongocrypt_ctx_setopt_schema.