update pool func visibility

contracts/gas-snapshots/ccip.gas-snapshot

@@ -943,13 +943,13 @@ TokenProxy_getFee:test_GetFeeInvalidToken_Revert() (gas: 12658)
 TokenProxy_getFee:test_GetFeeNoDataAllowed_Revert() (gas: 15849)
 TokenProxy_getFee:test_GetFee_Success() (gas: 86702)
 USDCTokenPool__validateMessage:test_ValidateInvalidMessage_Revert() (gas: 25290)
-USDCTokenPool_lockOrBurn:test_CallerIsNotARampOnRouter_Revert() (gas: 35322)
-USDCTokenPool_lockOrBurn:test_LockOrBurnWithAllowList_Revert() (gas: 30073)
-USDCTokenPool_lockOrBurn:test_LockOrBurn_Success() (gas: 133102)
-USDCTokenPool_lockOrBurn:test_UnknownDomain_Revert() (gas: 477183)
-USDCTokenPool_releaseOrMint:test_ReleaseOrMintRealTx_Success() (gas: 268111)
-USDCTokenPool_releaseOrMint:test_TokenMaxCapacityExceeded_Revert() (gas: 50676)
-USDCTokenPool_releaseOrMint:test_UnlockingUSDCFailed_Revert() (gas: 98591)
+USDCTokenPool_lockOrBurn:test_CallerIsNotARampOnRouter_Revert() (gas: 35397)
+USDCTokenPool_lockOrBurn:test_LockOrBurnWithAllowList_Revert() (gas: 30148)
+USDCTokenPool_lockOrBurn:test_LockOrBurn_Success() (gas: 133177)
+USDCTokenPool_lockOrBurn:test_UnknownDomain_Revert() (gas: 477258)
+USDCTokenPool_releaseOrMint:test_ReleaseOrMintRealTx_Success() (gas: 268172)
+USDCTokenPool_releaseOrMint:test_TokenMaxCapacityExceeded_Revert() (gas: 50733)
+USDCTokenPool_releaseOrMint:test_UnlockingUSDCFailed_Revert() (gas: 98648)
 USDCTokenPool_setDomains:test_InvalidDomain_Revert() (gas: 66150)
 USDCTokenPool_setDomains:test_OnlyOwner_Revert() (gas: 11333)
 USDCTokenPool_supportsInterface:test_SupportsInterface_Success() (gas: 9876)

contracts/src/v0.8/ccip/pools/USDC/USDCTokenPool.sol

@@ -93,13 +93,32 @@ contract USDCTokenPool is TokenPool, ITypeAndVersion {
     emit ConfigSet(address(tokenMessenger));
   }
 
+  /// @notice Burns USDC in the pool
+  /// @dev invokes underlying CCTP protocol
+  function lockOrBurn(Pool.LockOrBurnInV1 calldata lockOrBurnIn)
+    external
+    override
+    returns (Pool.LockOrBurnOutV1 memory lockOrBurnOut)
+  {
+    return _lockOrBurn(lockOrBurnIn);
+  }
+
+  /// @notice Mints USDC to the recipient
+  /// @dev invokes underlying CCTP protocol
+  function releaseOrMint(Pool.ReleaseOrMintInV1 calldata releaseOrMintIn)
+    external
+    override
+    returns (Pool.ReleaseOrMintOutV1 memory)
+  {
+    return _releaseOrMint(releaseOrMintIn);
+  }
+
   /// @notice Burn the token in the pool
   /// @dev emits ITokenMessenger.DepositForBurn
   /// @dev Assumes caller has validated destinationReceiver
-  function lockOrBurn(Pool.LockOrBurnInV1 calldata lockOrBurnIn)
-    external
+  function _lockOrBurn(Pool.LockOrBurnInV1 calldata lockOrBurnIn)
+    internal
     virtual
-    override
     returns (Pool.LockOrBurnOutV1 memory)
   {
     _validateLockOrBurn(lockOrBurnIn);
@@ -138,10 +157,9 @@ contract USDCTokenPool is TokenPool, ITypeAndVersion {
   /// for that message, including its (nonce, sourceDomain). This way, the only
   /// non-reverting offchainTokenData that can be supplied is a valid attestation for the
   /// specific message that was sent on source.
-  function releaseOrMint(Pool.ReleaseOrMintInV1 calldata releaseOrMintIn)
-    external
+  function _releaseOrMint(Pool.ReleaseOrMintInV1 calldata releaseOrMintIn)
+    internal
     virtual
-    override
     returns (Pool.ReleaseOrMintOutV1 memory)
   {
     _validateReleaseOrMint(releaseOrMintIn);