Avoid allocating temporary basic_json for cbor and msgpack object keys - #5328
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Signed-off-by: alexprabhat99 <alexpbara@gmail.com>
Signed-off-by: alexprabhat99 <alexpbara@gmail.com>
Signed-off-by: alexprabhat99 <alexpbara@gmail.com>
Signed-off-by: alexprabhat99 <alexpbara@gmail.com>
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This PR optimizes CBOR and MessagePack serialization by avoiding the construction of a temporary basic_json object for every object key during serialization.
Previously, object keys were passed through write_cbor()/write_msgpack(), which expected a BasicJsonType and therefore implicitly constructed a temporary basic_json for each key. This introduced unnecessary heap allocations during serialization.
This change factors out the string serialization logic into dedicated helper functions and serializes object keys directly. The implementation preserves compatibility with custom object key types while eliminating the extra basic_json allocations for the common case where object_t::key_type is string_t.
A regression test has been added to verify compatibility with custom object key types.
Fixes #5318