Redefine the return value

Clarify the true/false expectation and add optional stale value return.

specification/logs/bridge-api.md

@@ -145,12 +145,9 @@ parameters to be added.
 
 This API MUST return a language idiomatic boolean type.
 
-The returned value MUST be `true` when logging is enabled for the provided
-arguments. The returned value can be `true` or `false` when logging is disabled
-for the provided arguments. The ambiguity when disabled allows implementation
-that want to optimize memory or handle indeterminable states the flexibility
-they need. If an implementation does not need this flexibility, it SHOULD
-return `false` when logging is disabled for the provided arguments.
+Implementations of this API SHALL return `true` when logging is enabled or
+`false` when logging is disabled for the provided arguments. Implementations
+designed for performance that cache the logging state MAY return stale values.
 
 The returned value is not always static, it can change over time. The API
 SHOULD be documented that users needs to call this API each time they generate