private static GraphQLSchema buildSchema(
      final String sdl, final GraphQLDataFetchers graphQLDataFetchers) {
    final TypeDefinitionRegistry typeRegistry = new SchemaParser().parse(sdl);
    final RuntimeWiring runtimeWiring = buildWiring(graphQLDataFetchers);
    final SchemaGenerator schemaGenerator = new SchemaGenerator();
    return schemaGenerator.makeExecutableSchema(typeRegistry, runtimeWiring);
  }
Builds the GraphQL service with the provided data fetchers.

@param graphQLDataFetchers the data fetchers to be used in the GraphQL service.
@return the built GraphQL service.
@throws IOException if there is an error reading the schema file.
ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/graphql/GraphQLProvider.java