We currently have computeHmacWithContext to reuse context across hmac computations. As part of SPM-4740, we will need to compute multiple hashes within the same context. The current method computeHash allocates and deallocates a new EVP_MD_CTX for each operation. As a performance optimization, we will implement a HashContext class and a computeHashWithContext method with support for SHA-256 to support reusing the context across these hash computations.