default Container.ExecResult execInContainer(ExecConfig execConfig)
        throws UnsupportedOperationException, IOException, InterruptedException {
        return ExecInContainerPattern.execInContainer(getDockerClient(), getContainerInfo(), execConfig);
    }
Run a command inside a running container, as though using "docker exec".
core/src/main/java/org/testcontainers/containers/ContainerState.java