feat: `SSEResponse` class for streaming Server-Side Events (#9931) #14216

Job	Run time
Setup PHP Version for Code Coverage	4s
Others (8.4) / Sanity Tests	2m 36s
Others (8.5) / Sanity Tests	2m 32s
Others (8.2) / Sanity Tests	3m 49s
Others (8.3) / Sanity Tests	2m 39s
SeparateProcess (8.4) / tests	3m 34s
CacheLive (8.3) / Cache Live Tests	2m 15s
DatabaseLive (8.4, SQLite3, 8.0) / tests	2m 19s
CacheLive (8.2) / Cache Live Tests	2m 20s
CacheLive (8.5) / Cache Live Tests	2m 6s
SeparateProcess (8.3) / tests	3m 33s
SeparateProcess (8.5) / tests	3m 33s
DatabaseLive (8.3, SQLSRV, 8.0) / tests	5m 50s
DatabaseLive (8.3, Postgre, 8.0) / tests	2m 50s
CacheLive (8.4) / Cache Live Tests	2m 0s
DatabaseLive (8.3, MySQLi, 8.0) / tests	4m 36s
DatabaseLive (8.2, SQLSRV, 8.0) / tests	5m 51s
DatabaseLive (8.2, MySQLi, 5.7) / tests	4m 3s
SeparateProcess (8.2) / tests	3m 18s
DatabaseLive (8.4, OCI8, 8.0) / tests	6m 29s
DatabaseLive (8.5, SQLite3, 8.0) / tests	2m 22s
DatabaseLive (8.2, MySQLi, 8.0) / tests	5m 17s
DatabaseLive (8.4, MySQLi, 8.0) / tests	5m 26s
DatabaseLive (8.4, Postgre, 8.0) / tests	2m 54s
DatabaseLive (8.2, OCI8, 8.0) / tests	7m 32s
DatabaseLive (8.3, OCI8, 8.0) / tests	7m 1s
DatabaseLive (8.5, Postgre, 8.0) / tests	2m 53s
DatabaseLive (8.5, MySQLi, 8.0) / tests	4m 3s
DatabaseLive (8.5, OCI8, 8.0) / tests	6m 47s
DatabaseLive (8.4, SQLSRV, 8.0) / tests	5m 31s
DatabaseLive (8.2, SQLite3, 8.0) / tests	2m 57s
DatabaseLive (8.3, SQLite3, 8.0) / tests	2m 23s
DatabaseLive (8.2, Postgre, 8.0) / tests	3m 10s
DatabaseLive (8.5, SQLSRV, 8.0) / tests	6m 2s
Upload coverage results to Coveralls / coveralls	42s
	2h 11m 17s

Provide feedback