anchor.diff:  If you need to customize the pre-processing of the Token Request, you can provide `DefaultClientCredentialsTokenResponseClient.setRequestEntityConverter()` with a custom `Converter<OAuth2ClientCredentialsGrantRequest, RequestEntity<?>>`.
   The default implementation `OAuth2ClientCredentialsGrantRequestEntityConverter` builds a `RequestEntity` representation of a standard https://tools.ietf.org/html/rfc6749#section-4.4.2[OAuth 2.0 Access Token Request].
   However, providing a custom `Converter`, would allow you to extend the standard Token Request and add custom parameter(s).
  +
  +To customize only the parameters of the request, you can provide `OAuth2ClientCredentialsGrantRequestEntityConverter.setParametersConverter()` with a custom `Converter<OAuth2ClientCredentialsGrantRequest, MultiValueMap<String, String>>` to completely override the parameters sent with the request. This is often simpler than constructing a `RequestEntity` directly.
  +
  +[TIP]
  +If you prefer to only add additional parameters, you can provide `OAuth2ClientCredentialsGrantRequestEntityConverter.addParametersConverter()` with a custom `Converter<OAuth2ClientCredentialsGrantRequest, MultiValueMap<String, String>>` which constructs an aggregate `Converter`.
   
   IMPORTANT: The custom `Converter` must return a valid `RequestEntity` representation of an OAuth 2.0 Access Token Request that is understood by the intended OAuth 2.0 Provider.
   
  
positive.code: The default implementation `OAuth2RefreshTokenGrantRequestEntityConverter` builds a `RequestEntity` representation of a standard https://tools.ietf.org/html/rfc6749#section-6[OAuth 2.0 Access Token Request].
  However, providing a custom `Converter`, would allow you to extend the standard Token Request and add custom parameter(s).
  
  IMPORTANT: The custom `Converter` must return a valid `RequestEntity` representation of an OAuth 2.0 Access Token Request that is understood by the intended OAuth 2.0 Provider.
  
  
  
negative.code: The default implementation `JwtBearerGrantRequestEntityConverter` builds a `RequestEntity` representation of a https://datatracker.ietf.org/doc/html/rfc7523#section-2.1[OAuth 2.0 Access Token Request].
  However, providing a custom `Converter`, would allow you to extend the Token Request and add custom parameter(s).
  
  To customize only the parameters of the request, you can provide `JwtBearerGrantRequestEntityConverter.setParametersConverter()` with a custom `Converter<JwtBearerGrantRequest, MultiValueMap<String, String>>` to completely override the parameters sent with the request. This is often simpler than constructing a `RequestEntity` directly.
  
  [TIP]
  If you prefer to only add additional parameters, you can provide `JwtBearerGrantRequestEntityConverter.addParametersConverter()` with a custom `Converter<JwtBearerGrantRequest, MultiValueMap<String, String>>` which constructs an aggregate `Converter`.
  
  
  ==== Customizing the Access Token Response
  
  