@Internal
  @Nullable
  Path getExecutablePath() {
    if (System.getProperty(PropertyNames.DOCKER_CLIENT_EXECUTABLE) != null) {
      return Paths.get(System.getProperty(PropertyNames.DOCKER_CLIENT_EXECUTABLE));
    }
    return executable;
  }
Object that configures the Docker executable and the additional environment variables to use when
executing the executable.
jib-gradle-plugin/src/main/java/com/google/cloud/tools/jib/gradle/DockerClientParameters.java