09-localhost 轻客户端模块会在核心 IBC 模块内部注册编解码器类型。这与其他轻客户端模块实现不同，后者通常应通过 AppModuleBasic 接口注册编解码器类型。 localhost 客户端可通过在 02-client 子模块中将参数 allowed_clients 的默认值设为 AllowAllClients 通配符（"*"）来隐式启用。 
/ DefaultAllowedClients are the default clients for the AllowedClients parameter.
/ By default it allows all client types.
var DefaultAllowedClients = []string{
    AllowAllClients
}
The 09-localhost light client module registers codec types within the core IBC module. This differs from other light client module implementations which are expected to register codec types using the AppModuleBasic interface. The localhost client is implicitly enabled by using the AllowAllClients wildcard ("*") in the 02-client submodule default value for param allowed_clients. 
/ DefaultAllowedClients are the default clients for the AllowedClients parameter.
/ By default it allows all client types.
var DefaultAllowedClients = []string{
    AllowAllClients
}