This is used in FaaS performance analysis program.
(1). 权限检查：
(2). /sap/opu/odata/sap/CRM_APPOINTMENT_SRV/AppointmentSet(guid’3440B5B1-72DE-1EE5-8AA1-4A211B548898’)
取ETAG:
这个ETAG会在save button被调用时使用到：
(3).
(4). 取complex note：
cloud version
(1). GET /sap/opu/odata/sap/CRM_APPOINTMENT_SRV/EditAuthorizationCheck?ObjectGuid=guid’3440B5B1-6F66-1EE5-82B4-A9B3DA66921D’ HTTP/1.1 - 权限检查
(2). GET /sap/opu/odata/sap/CRM_APPOINTMENT_SRV/AppointmentSet(guid’3440B5B1-6F66-1EE5-82B4-A9B3DA66921D’)?$expand=Attendee,AppointmentToAttachment HTTP/1.1
这个roundtrip是在NewAppointment.js的editAppointment里trigger的，同步。
(3). 拿CSRF token，因为接下来是http post：
(4). http post - batch
POST /sap/opu/odata/sap/CRM_APPOINTMENT_SRV/$batch HTTP/1.1
a. GET AppointmentSet(guid’3440B5B1-6F66-1EE5-82B4-A9B3DA66921D’)/AppointmentStatuses HTTP/1.1
b. GET UserPriorities HTTP/1.1
拿drop down list里status和priority里的entry：
user status：
