CrossmintClient.
CrossmintApiConfig (the shared base shape used across all
Crossmint SDK platforms) with the Flutter-specific plug-points
authStorage, logger, refreshRoute, and logoutRoute.
ck_*) for frontend apps — they require origin
for auth. Use a server key (sk_*) only in server contexts; it needs
no origin.
Constructors
CrossmintClientConfig
CrossmintClientConfig.
Properties
authStorage
FlutterSecureStorage under the hood.
logger
debugPrint-backed logger in debug.

