Early Numbering is one of the Numbering concept in RAP which helps to set the primary key values at the time of creating instances.
In this video, I have explained internal unmanaged option where developer needs to generates primary key field values via behavior implementation. This feature will be helpful in case the primary key field need to generate using number ranges (SNRO) or any another logic
Managed Early Numbering - • Early Numbering in SAP RAP | Internal & M...
SAP RAP playlist - • Managed Restful ABAP Programming Model (RAP)