key prefix (empty for direct methods, conn:{refId}: for connection calls)
method: string
method name
args: unknown[]
raw call arguments
Returns string
Description
Builds a deterministic call key used for snapshot lookup.
Format: prefix + method + ':' + stableHash(args).
Functions in args are replaced with MARKER_CALLBACK before hashing.
key prefix (empty for direct methods,
conn:{refId}:for connection calls)