/github/workspace/Packages/src/Runtime/Internal/Utilities/ShaderVariantRegistry.cs(14,6): error CS0246: The type or namespace name 'SerializableAttribute' could not be found (are you missing a using directive or an assembly reference?)

/github/workspace/Packages/src/Runtime/Internal/Utilities/ShaderVariantRegistry.cs(14,6): error CS0246: The type or namespace name 'Serializable' could not be found (are you missing a using directive or an assembly reference?)

/github/workspace/Packages/src/Runtime/Internal/Utilities/ShaderVariantRegistry.cs(17,10): error CS0246: The type or namespace name 'SerializableAttribute' could not be found (are you missing a using directive or an assembly reference?)

/github/workspace/Packages/src/Runtime/Internal/Utilities/ShaderVariantRegistry.cs(17,10): error CS0246: The type or namespace name 'Serializable' could not be found (are you missing a using directive or an assembly reference?)

/github/workspace/Packages/src/Runtime/Internal/Utilities/ShaderVariantRegistry.cs(17,10): error CS0246: The type or namespace name 'SerializableAttribute' could not be found (are you missing a using directive or an assembly reference?)

/github/workspace/Packages/src/Runtime/Internal/Utilities/ShaderVariantRegistry.cs(17,10): error CS0246: The type or namespace name 'Serializable' could not be found (are you missing a using directive or an assembly reference?)

Error building Player because scripts had compiler errors

Build failed with exit code 101

Library folder does not exist. Consider setting up caching to speed up your workflow, if this is not your first build.

Activation failed, attempting retry #1