Configurable timeout for client startup and shout down

In some rear cases load on a computer can be so high that the startup
and shoutdown may use longer than the hard coded 30 seconds. This
change make these configurable to handle these cases.

src/prefect/client/base.py

@@ -18,6 +18,8 @@
 from prefect.settings import (
     PREFECT_CLIENT_RETRY_EXTRA_CODES,
     PREFECT_CLIENT_RETRY_JITTER_FACTOR,
+    PREFECT_CLIENT_LIFESPAN_CONTEXT_STARTUP_TIMEOUT,
+    PREFECT_CLIENT_LIFESPAN_CONTEXT_SHOUTDOWN_TIMEOUT,
 )
 from prefect.utilities.math import bounded_poisson_interval, clamped_poisson_interval
 
@@ -88,7 +90,9 @@ async def app_lifespan_context(app: FastAPI) -> ContextManager[None]:
         else:
             # Create a new lifespan manager
             APP_LIFESPANS[key] = context = LifespanManager(
-                app, startup_timeout=30, shutdown_timeout=30
+                app,
+                startup_timeout=PREFECT_CLIENT_LIFESPAN_CONTEXT_STARTUP_TIMEOUT.value(),
+                shutdown_timeout=PREFECT_CLIENT_LIFESPAN_CONTEXT_SHOUTDOWN_TIMEOUT.value(),
             )
             APP_LIFESPANS_REF_COUNTS[key] = 1
 

src/prefect/settings.py

@@ -1042,6 +1042,28 @@ def default_cloud_ui_url(settings, value):
 API with another tool you will need to configure this there instead.
 """
 
+PREFECT_CLIENT_LIFESPAN_CONTEXT_STARTUP_TIMEOUT = Setting(
+    int,
+    default=30,
+)
+"""
+The time the client has to startup before we expect it has failed
+without reporting back.
+
+The client may in extreme load use an unknown starting up.
+"""
+
+PREFECT_CLIENT_LIFESPAN_CONTEXT_SHOUTDOWN_TIMEOUT = Setting(
+    int,
+    default=30,
+)
+"""
+The time the client has to shouting down before we expect it has
+failed without completed.
+
+The client may in extreme load use an unknown shouting down.
+"""
+
 PREFECT_UI_ENABLED = Setting(
     bool,
     default=True,