ServiceClient constructor
Creates a ServiceClient using client for transport.
The provided http.Client must be configured to provide whatever
authentication is required by the API being accessed. You can do that
using
package:googleapis_auth.
If gapicVersion is set, gapic/<version> is included in the
x-goog-api-client header.
If gcclVersion is set, gccl/<version> is included in the
x-goog-api-client header.
Both gapicVersion and gcclVersion should be set if the library
includes both automatically-generated and hand-written components.
For example, package:google_cloud_firestore (hand-written) wraps
package:google_cloud_firestore_v1 (generated).
Implementation
ServiceClient({required this.client, this.gapicVersion, this.gcclVersion});