Nsight NIC plugin fails with `-Wextra -Werror` due to partially initialized `nvtxPayloadSchemaEntry_t`

[GregoryKimball]

When KvikIO is built as a dependency of a project that enables -Wextra, the Nsight NIC plugin fails because two nvtxPayloadSchemaEntry_t instances omit several fields.

KvikIO adds -Werror to this target, so the warnings become errors:

error: missing initializer for member ‘nvtxPayloadSchemaEntry_v1::flags’
error: missing initializer for member ‘nvtxPayloadSchemaEntry_v1::arrayOrUnionDetail’
error: missing initializer for member ‘nvtxPayloadSchemaEntry_v1::semantics’
error: missing initializer for member ‘nvtxPayloadSchemaEntry_v1::reserved’
[-Werror=missing-field-initializers]

Environment:

• CUDA 13.1
• GCC 14
• Nsight Systems CLI 2026.3.1
• KvikIO commit 496acd8
• The same initializer remains on current KvikIO main
• Consumer compiler flags: -Wextra
• Plugin compiler flags: -Wall -Werror

Expected fix:

Value-initialize each nvtxPayloadSchemaEntry_t and assign the required fields, or explicitly initialize the remaining fields to zero/null. Value initialization followed by assignment is preferable because it remains safe if NVTX adds more fields later.

Proposed fix in cpp/nsys_plugins/nic/kvikio_nic_nsys_plugin.cpp:

auto make_entry = [](char const* name, char const* description, std::size_t offset) {
  nvtxPayloadSchemaEntry_t entry{};
  entry.type        = NVTX_PAYLOAD_ENTRY_TYPE_DOUBLE;
  entry.name        = name;
  entry.description = description;
  entry.offset      = offset;
  return entry;
};
std::array const entries = {
  make_entry("rx", "Receive rate", offsetof(NicRates, rx)),
  make_entry("tx", "Transmit rate", offsetof(NicRates, tx)),
};