decisions: binary

doc/decisions/README.md

@@ -62,6 +62,7 @@ section here.
 ## In Discussion
 
 - [simplify API](simplify_api.md)
+- [Binary](binary.md)
 - [keyString() return value](key_string_return_value.md)
 - [Global Plugins](global_plugins.md) (@mpranj)
 - [Error Semantics](error_semantics.md) (API)

doc/decisions/binary.md

@@ -0,0 +1,35 @@
+# Binary
+
+## Problem
+
+binary
+
+- is the only metadata that allows more values (instead of making the validation stricter)
+- is the only API that modifies metadata
+
+## Constraints
+
+- simplify API
+
+## Assumptions
+
+binary values are a rarely used feature
+
+## Considered Alternatives
+
+- flag for indicating if a value is binary
+
+## Decision
+
+- make keys binary per default
+- all current types are not binary, so type = string is the way to indicate a string doesn't
+  - contain null bytes
+  - is not null
+
+## Rationale
+
+## Implications
+
+## Related Decisions
+
+## Notes