if (!currentImplementation.getClassIdentifier().equals(previousImplementation.getClassIdentifier())) {
            return visitor.visitChange(new DescriptiveChange("The type of %s has changed from '%s' to '%s'.",
                executable.getDisplayName(), previousImplementation.getClassIdentifier(), currentImplementation.getClassIdentifier()));
        }

    }

    protected ImplementationSnapshot(String classIdentifier) {
        this.classIdentifier = classIdentifier;
    }

    public String getClassIdentifier() {
        return classIdentifier;
    }

    @Nullable
    public abstract HashCode getClassLoaderHash();

    @Override

            }
        };

        @Override
        public void write(Encoder encoder, ImplementationSnapshot implementationSnapshot) throws Exception {
            encoder.writeString(implementationSnapshot.getClassIdentifier());
            writeAdditionalData(encoder, implementationSnapshot);
        }

        @Override
        public ImplementationSnapshot read(Decoder decoder) throws Exception {

    }

    @Nullable
    public String getImplementationClassName() {
        return getBeforeExecutionState()
            .map(ExecutionInputState::getImplementation)
            .map(ImplementationSnapshot::getClassIdentifier)
            .orElse(null);
    }

    @Nullable
    public List<byte[]> getActionClassLoaderHashesBytes() {
        return getBeforeExecutionState()