code: public void registerTenant(String tenantId, DataSource dataSource) {
      ((TenantAwareDataSource) super.getDataSource()).addDataSource(tenantId, dataSource);
      
      if (booted) {
        createTenantSchema(tenantId);
        
        createTenantAsyncJobExecutor(tenantId);
        
        tenantInfoHolder.setCurrentTenantId(tenantId);
        super.postProcessEngineInitialisation();
        tenantInfoHolder.clearCurrentTenantId();
      }
    }
docs: Add a new {@link DataSource} for a tenant, identified by the provided tenantId, to the engine.
  This can be done after the engine has booted up.
  
  Note that the tenant identifier must have been added to the {@link TenantInfoHolder} *prior*
  to calling this method.