New creates a new instance of the Slack service client.

WithHTTPClient overrides the default HTTP client.

WithPingTimeout overrides the default ping timeout.

WithPingURL overrides the default ping timeout.

WithRetryAttempts overrides the default HTTP client.

WithTimeout overrides the default request timeout.

Client is the implementation of the service client.

HTTPClient contains the function to perform the actual HTTP request.

Option is the interface that allows to set client options.