In Chapter 1, Hello Rust!, we discussed Send, a marker trait that allows a type to be "sent" across multiple threads. Something that's similar but less complex is local moving, which commonly occurs in a program—for example, when you pass a variable into a function.
Copying and cloning, on the other hand, happen on different occasions. When a variable is assigned to another variable, the compiler will typically copy the value implicitly, which can be done safely and cheaply for stack-allocated variables.
Copy is an implicit, bitwise copy of the value of a variable. If that variable is a pointer, the memory responsibility becomes ambiguous (who takes care of freeing?) and compilation will fail. This is where Clone comes in. The trait requires an explicit implementation of the clone() function to provide an appropriate copy of the type.
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