Memory leak in AWSV4

==12599== 642 bytes in 3 blocks are definitely lost in loss record 546 of 636
==12599== at 0x4C2AB68: operator new[](unsigned long) (vg_replace_malloc.c:433)
==12599== by 0xC5C0AB4: AWSV4::sha256(std::string, unsigned char*) (awsv4.cc:68)
==12599== by 0xC5C0B97: AWSV4::sha256_base16(std::string) (awsv4.cc:82)
==12599== by 0xC5C33B4: AWSV4::compute_awsv4_signature(std::string const&, long const&, std::string const&, std::string const&, std::string const&, std::string const&, bool const&) (awsv4.cc:495)
==12599== by 0xC5879E9: dmrpp::CurlHandlePool::get_easy_handle(dmrpp::Chunk*) (CurlHandlePool.cc:827)
==12599== by 0xC575211: dmrpp::Chunk::read_chunk() (Chunk.cc:550)
==12599== by 0xC58D10E: dmrpp:mrppArray::read_contiguous() (DmrppArray.cc:509)
==12599== by 0xC5916C0: dmrpp:mrppArray::read() (DmrppArray.cc:1232)
==12599== by 0x577A301: libdap::Vector::serialize(libdap:4StreamMarshaller&, libdap:MR&, bool) (Vector.cc:951)
==12599== by 0x57FC79D: libdap:4Group::serialize(libdap:4StreamMarshaller&, libdap:MR&, bool) (D4Group.cc:538)
==12599== by 0xC066953: BESDapResponseBuilder::serialize_dap4_data(std::ostream&, libdap:MR&, bool) (BESDapResponseBuilder.cc:1466)
==12599== by 0xC0661F7: BESDapResponseBuilder::send_dap4_data_using_ce(std::ostream&, libdap:MR&, bool) (BESDapResponseBuilder.cc:1407)