I am trying to call one rest API using Httprequest (from salesforce using Apex code), but not able to figure how I can pass the body.  I would appreciate if anyone share the way to pass the below mentioned body in the HttpRequest.

here are the details:
End-point URL : https://api.boomi.com/api/rest/v1/AccountID/EnvironmentExtensions/XXXXXXXXXX

Body:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<bns:EnvironmentExtensions xmlns:bns="http://api.platform.boomi.com/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" id="XXXXXXXXXXXXXXXX" extensionGroupId="" environmentId="XXXXXXXXXXXXXXX">
    <bns:connections>
        <bns:connection name="SFDC connection" id="XXXX">
            <bns:field componentOverride="false" usesEncryption="false" encryptedValueSet="false" value="email@gmail.com" id="user"/>
            <bns:field componentOverride="false" usesEncryption="true" encryptedValueSet="true" id="password" value="password"/>
        </bns:connection>
    </bns:connections>
</bns:EnvironmentExtensions>


Apex code to call Rest API:


      String endPointURL = 'https://api.boomi.com/api/rest/v1/AccountID/EnvironmentExtensions/XXXXXXXXXX';
      
      String userName = 'XXXXXX';
      String password = 'XXXXXXX';

      String body= '';
      String query;
      query = '';
      Blob headerValue = Blob.valueOf(userName + ':' + password);
      String authorizationHeader = 'BASIC ' +
      EncodingUtil.base64Encode(headerValue);
      accs1 = new List<cAccount>();
      Httprequest request = new HttpRequest();
      Http http = new Http();
      request.setMethod('POST');
      request.setEndpoint(endPointURL);
      request.setHeader('Content-Type', 'application/json');
      // Header info with remote server user name and password
      request.setHeader('Authorization', authorizationHeader);
      request.setBody(query); 
            
      request.setTimeout(120000); 
      request.setBody(query);          
      //Making call to external REST API
      HttpResponse response = http.send(request);  
      System.debug('responseBody: '+response.getBody());