SSL_CTX_has_client_custom_ext - check whether a handler exists for a particular client extension type
#include <openssl/ssl.h>
int SSL_CTX_has_client_custom_ext(const SSL_CTX *ctx, unsigned int ext_type);
SSL_CTX_has_client_custom_ext() checks whether a handler has been set for a client extension of type ext_type using SSL_CTX_add_client_custom_ext().
Returns 1 if a handler has been set, 0 otherwise.