public CreateUserPoolRequest withUsernameConfiguration(UsernameConfigurationType usernameConfiguration) {
        setUsernameConfiguration(usernameConfiguration);
        return this;
    }
<p>
Case sensitivity on the username input for the selected sign-in option. When case sensitivity is set to
<code>False</code> (case insensitive), users can sign in with any combination of capital and lowercase letters.
For example, <code>username</code>, <code>USERNAME</code>, or <code>UserName</code>, or for email,
<code>email@example.com</code> or <code>EMaiL@eXamplE.Com</code>. For most use cases, set case sensitivity to
<code>False</code> (case insensitive) as a best practice. When usernames and email addresses are case
insensitive, Amazon Cognito treats any variation in case as the same user, and prevents a case variation from
being assigned to the same attribute for a different user.
</p>
<p>
This configuration is immutable after you set it. For more information, see <a href=
"https://docs.aws.amazon.com/cognito-user-identity-pools/latest/APIReference/API_UsernameConfigurationType.html"
>UsernameConfigurationType</a>.
</p>

@param usernameConfiguration
       Case sensitivity on the username input for the selected sign-in option. When case sensitivity is set to
       <code>False</code> (case insensitive), users can sign in with any combination of capital and lowercase
       letters. For example, <code>username</code>, <code>USERNAME</code>, or <code>UserName</code>, or for
       email, <code>email@example.com</code> or <code>EMaiL@eXamplE.Com</code>. For most use cases, set case
       sensitivity to <code>False</code> (case insensitive) as a best practice. When usernames and email
       addresses are case insensitive, Amazon Cognito treats any variation in case as the same user, and prevents
       a case variation from being assigned to the same attribute for a different user.</p>
       <p>
       This configuration is immutable after you set it. For more information, see <a href=
       "https://docs.aws.amazon.com/cognito-user-identity-pools/latest/APIReference/API_UsernameConfigurationType.html"
       >UsernameConfigurationType</a>.
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-cognitoidp/src/main/java/com/amazonaws/services/cognitoidp/model/CreateUserPoolRequest.java