@Test fun ofMapAcceptsEmptyValue() {
    val headers = mapOf("User-Agent" to "").toHeaders()
    assertThat(headers.value(0)).isEqualTo("")
  }

  @Test fun ofMapTrimsKey() {
    val headers = mapOf(" User-Agent " to "OkHttp").toHeaders()
    assertThat(headers.name(0)).isEqualTo("User-Agent")
  }

  @Test fun ofMapTrimsValue() {
    val headers = mapOf("User-Agent" to " OkHttp ").toHeaders()

On the other side, there are thousands of users in the chat systems, so there's a high chance you'll find someone to talk to there, almost all the time. 😄

## Sponsor the author { #sponsor-the-author }

   * accomplished with {@link Optional#or(Object) first.or(second)}. That approach also allows for
   * lazy evaluation of the fallback instance, using {@link Optional#or(Supplier)
   * first.or(supplier)}.
   *
   * <p><b>Java 9 users:</b> use {@code java.util.Objects.requireNonNullElse(first, second)}
   * instead.
   *
   * @return {@code first} if it is non-null; otherwise {@code second} if it is non-null

    if (pooled3 != null) return pooled3.connection

    connection.withLock {
      connectionPool.put(connection)
      user.acquireConnectionNoEvents(connection)
    }

    user.connectionAcquired(connection)
    user.connectionConnectionAcquired(connection)
    return connection
  }

  override fun trackFailure(
    call: RealCall,
    e: IOException?,
  ) {

    // Helper method to create test user
    private User createTestUser(String username, String password) {
        User user = new User();
        user.setName(username);
        user.setPassword(password);
        user.setRoles(new String[] { "role1", "role2" });
        user.setGroups(new String[] { "group1", "group2" });
        return user;
    }

    // Test LdapManager implementation

		Result        string
	}{
		{
			SQL:           "create table users (name, age, height, actived, bytes, create_at, update_at, deleted_at, email, role, pass) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
			NumericRegexp: nil,
			Vars:          []interface{}{"jinzhu", 1, 999.99, true, []byte("12345"), tt, &tt, nil, "w@g.\"com", myrole, pwd},

 *       collection. Undefined behavior and bugs will result. It's generally best to avoid using
 *       mutable objects as elements at all, as many users may expect your "immutable" object to be
 *       <i>deeply</i> immutable.
 * </ul>
 *
 * <h4>Performance notes</h4>
 *
 * <ul>

				clause.Set([]clause.Assignment{{clause.PrimaryColumn, 1}}),
			},
			"UPDATE `users` SET `users`.`id`=?",
			[]interface{}{1},
		},
		{
			[]clause.Interface{
				clause.Update{},
				clause.Set([]clause.Assignment{{clause.PrimaryColumn, 1}}),
				clause.Set([]clause.Assignment{{clause.Column{Name: "name"}, "jinzhu"}}),
			},
			"UPDATE `users` SET `name`=?",
			[]interface{}{"jinzhu"},
		},
	}

///

## Advanced User Guide { #advanced-user-guide }

There is also an **Advanced User Guide** that you can read later after this **Tutorial - User guide**.

The **Advanced User Guide** builds on this one, uses the same concepts, and teaches you some extra features.

But you should first read the **Tutorial - User Guide** (what you are reading right now).

				[]clause.Column{clause.PrimaryColumn},
			}},
			"SELECT * FROM `users` RETURNING `users`.`id`", nil,
		}, {
			[]clause.Interface{clause.Select{}, clause.From{}, clause.Returning{
				[]clause.Column{clause.PrimaryColumn},
			}, clause.Returning{
				[]clause.Column{{Name: "name"}, {Name: "age"}},
			}},
			"SELECT * FROM `users` RETURNING `users`.`id`,`name`,`age`", nil,
		},
		{