curl -X POST https://api.box.com/2.0/task_assignments \
     -H 'Authorization: Bearer <ACCESS_TOKEN>" '
     -H 'Content-Type: application/json" '
     -d '{
       "task": {
         "id": "11446498",
         "type": "task"
       },
       "assign_to": {
         "id": "4823213"
       }
     }'

// Assign task 11111 to user 22222
var assignmentParams = new BoxTaskAssignmentRequest()
{
    Task = new BoxTaskRequest()
    {
        Id = "11111"
    },
    AssignTo = new BoxAssignmentRequest()
    {
        Id = "22222"
    }
};
BoxTaskAssignment assignment = await client.TasksManager.CreateTaskAssignmentAsync(assignmentParams);

BoxUser user = new BoxUser(api, "user-id")
BoxTask task = new BoxTask(api, "id");
task.addAssignment(user);

user = client.user(user_id='11111')
assignment = client.task(task_id='12345').assign(user)
print('Assignment ID is {0} and is assigned to user {1}'.format(assignment.id, assignment.assigned_to.name))

// Assign task 11111 to user 22222
var taskID = '11111';
var userID = '22222';
client.tasks.assignByUserID(taskID, userID)
	.then(assignment => {
		/* assignment -> {
			type: 'task_assignment',
			id: '12345',
			item: 
			{ type: 'file',
				id: '33333',
				sequence_id: '0',
				etag: '0',
				sha1: '7840095ee096ee8297676a138d4e316eabb3ec96',
				name: 'script.js' },
			assigned_to: 
			{ type: 'user',
				id: '22222',
				name: 'Sample Assignee',
				login: 'assignee@exmaple.com' },
			message: null,
			completed_at: null,
			assigned_at: '2013-05-10T11:43:41-07:00',
			reminded_at: null,
			resolution_state: 'incomplete',
			assigned_by: 
			{ type: 'user',
				id: '33333',
				name: 'Example User',
				login: 'user@example.com' } }
		*/
	});