You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: client_config.go
    path of file: ./repos/faas-netes/vendor/k8s.io/client-go/tools/clientcmd
    
    the code of the file until where you have to start completion: /*
Copyright 2014 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations
    
func (config *DirectClientConfig) ClientConfig() (*restclient.Config, error) {
	// check that getAuthInfo, getContext, and getCluster do not return an error.
	// Do this before checking if the current config is usable in the event that an
	// AuthInfo, Context, or Cluster config with user-defined names are not found.
	// This provides a user with the immediate cause for error if one is found
	configAuthInfo, err := config.getAuthInfo()
	if err != nil {
		return nil, err
	}

	_, err = config.getContext()
	if err != nil {
		return nil, err
	}

	configClusterInfo, err := config.getCluster()
	if err != nil {
		return nil, err
	}

	if err := config.ConfirmUsable(); err != nil {
		return nil, err
	}

	clientConfig := &restclient.Config{}
	clientConfig.Host = configClusterInfo.Server
	if configClusterInfo.ProxyURL != "" {
		u, err := parseProxyURL(configClusterInfo.ProxyURL)
		if err != nil {
			return nil, err
		}
		clientConfig.Proxy = http.ProxyURL(u)
	}

	clientConfig.DisableCompression = configClusterInfo.DisableCompression

	if config.overrides != nil && len(config.overrides.Timeout) > 0 {
		timeout, err := ParseTimeout(config.overrides.Timeout)
		if err != nil {
			return nil, err
		}
		clientConfig.Timeout = timeout
	}

	if u, err := url.ParseRequestURI(clientConfig.Host); err == nil && u.Opaque == "" && len(u.Path) > 1 {
		u.RawQuery = ""
		u.Fragment = ""
		clientConfig.Host = u.String()
	}
	if len(configAuthInfo.Impersonate) > 0 {
		clientConfig.Impersonate = restclient.ImpersonationConfig{
			UserName: configAuthInfo.Impersonate,
			UID:      configAuthInfo.ImpersonateUID,
			Groups:   configAuthInfo.ImpersonateGroups,
			Extra:    configAuthInfo.ImpersonateUserExtra,
		}
	}

	// only try to read the auth information if we are secure
	if restclient.IsConfigTransportTLS(*clientConfig) {
		var err error
		var persister restclient.AuthProviderConfigPersister
		if config.configAccess != nil {
			authInfoName, _ := config.getAuthInfoName()
			persister = PersisterForUser(config.configAccess, authInfoName)
		}
		userAuthPartialConfig, err := config.getUserIdentificationPartialConfig(configAuthInfo, config.fallbackReader, persister, configClusterInfo)
		if err != nil {
			return nil, err
		}
		mergo.Merge(clientConfig, userAuthPartialConfig, mergo.WithOverride)

		serverAuthPartialConfig, err := getServerIdentificationPartialConfig(configAuthInfo, configClusterInfo)
		if err != nil {
			return nil, err
		}
		mergo.Merge(clientConfig, serverAuthPartialConfig, mergo.WithOverride)
	}

	return clientConfig, nil
}