Message Mutability

Mutability indicates whether your program may modify a message:

  • A program may modify a mutable message by adding, deleting, or changing field values.
  • A program cannot modify an immutable message in any way.

Mutability depends entirely on the origin of a message.

Message Mutability Depends on Origin
Origin Mutability
Local A local message is mutable.
Inbound An inbound message is immutable, even if the subscriber released it to the callback.
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