partitioner: expose PartitionerName

There are two reasons to do so.
First, users may be interested which partitioner is used for a specific
PreparedStatement.
Second, tests in session_test.rs call `get_partitioner_name()` to assert
some things. If we want to extract `session_test.rs` to integration
tests directory - out of `scylla` crate - we must therefore expose
`get_partitioner_name().

NOTE: PartitionerHasherAny is made `pub` in this commit. This is a
temporary measure. This is needed because otherwise the compiler errors
out that we leak a crate-private type in public interface (the
associated type in `impl Partitioner for PartitionerName`).
We will be able to revert this once we unpub `Partitioner(Hasher)`.

Author: wprzytula

scylla/src/routing/partitioner.rs

@@ -16,8 +16,9 @@ use std::num::Wrapping;
 use crate::{prepared_statement::TokenCalculationError, routing::Token};
 
 #[allow(clippy::upper_case_acronyms)]
-#[derive(Clone, PartialEq, Debug, Default)]
-pub(crate) enum PartitionerName {
+#[derive(Clone, PartialEq, Eq, Debug, Default)]
+#[non_exhaustive]
+pub enum PartitionerName {
     #[default]
     Murmur3,
     CDC,
@@ -48,8 +49,9 @@ impl Partitioner for PartitionerName {
     }
 }
 
+// TODO: make this back `pub(crate)` in this PR.
 #[allow(clippy::upper_case_acronyms)]
-pub(crate) enum PartitionerHasherAny {
+pub enum PartitionerHasherAny {
     Murmur3(Murmur3PartitionerHasher),
     CDC(CDCPartitionerHasher),
 }

scylla/src/statement/prepared_statement.rs

@@ -418,7 +418,7 @@ impl PreparedStatement {
     }
 
     /// Get the name of the partitioner used for this statement.
-    pub(crate) fn get_partitioner_name(&self) -> &PartitionerName {
+    pub fn get_partitioner_name(&self) -> &PartitionerName {
         &self.partitioner_name
     }