Provide documentation for all SSL(_CTX)?_(get|set)(_default)?_read_ahead

=pod

=head1 NAME

SSL_CTX_set_read_ahead, SSL_CTX_set_default_read_ahead, SSL_CTX_get_read_ahead,

SSL_CTX_get_default_read_ahead, SSL_set_read_ahead, SSL_get_read_ahead

- manage whether to read as many input bytes as possible

=head1 SYNOPSIS

 #include <openssl/ssl.h>

 int SSL_get_read_ahead(const SSL *s);

 void SSL_set_read_ahead(SSL *s, int yes);

 #define SSL_CTX_get_default_read_ahead(ctx)

 #define SSL_CTX_set_default_read_ahead(ctx,m)

 #define SSL_CTX_get_read_ahead(ctx)

 #define SSL_CTX_set_read_ahead(ctx,m)

=head1 DESCRIPTION

SSL_CTX_set_read_ahead() and SSL_set_read_ahead() set whether we should read as

many input bytes as possible (for non-blocking reads) or not. For example if

B<x> bytes are currently required by OpenSSL, but B<y> bytes are available from

the underlying BIO (where B<y> > B<x>), then OpenSSL will read all B<y> bytes

into its buffer (providing that the buffer is large enough) if reading ahead is

on, or B<x> bytes otherwise. The parameter B<yes> or B<m> should be 0 to ensure

reading ahead is off, or non zero otherwise.

SSL_CTX_set_default_read_ahead is a synonym for SSL_CTX_set_read_ahead, and

SSL_CTX_get_default_read_ahead is a synonym for SSL_CTX_get_read_ahead.

SSL_CTX_get_read_ahead() and SSL_get_read_ahead() indicate whether reading

ahead has been set or not.

=head1 NOTES

These functions have no impact when used with DTLS. The return values for

SSL_CTX_get_read_head() and SSL_get_read_ahead() are undefined for DTLS.

=head1 RETURN VALUES

SSL_get_read_ahead and SSL_CTX_get_read_ahead return 0 if reading ahead is off,

and non zero otherwise.

=head1 SEE ALSO

L<ssl(3)|ssl(3)>

=cut

SSL_pending() takes into account only bytes from the TLS/SSL record

that is currently being processed (if any).  If the B<SSL> object's

I<read_ahead> flag is set, additional protocol bytes may have been

read containing more TLS/SSL records; these are ignored by

I<read_ahead> flag is set (see

L<SSL_CTX_set_read_ahead(3)|SSL_CTX_set_read_ahead(3)>), additional protocol

bytes may have been read containing more TLS/SSL records; these are ignored by

SSL_pending().

Up to OpenSSL 0.9.6, SSL_pending() does not check if the record type

=head1 SEE ALSO

L<SSL_read(3)|SSL_read(3)>, L<ssl(3)|ssl(3)>

L<SSL_read(3)|SSL_read(3)>,

L<SSL_CTX_set_read_ahead(3)|SSL_CTX_set_read_ahead(3)>, L<ssl(3)|ssl(3)>

=cut

=item int (*B<SSL_CTX_get_client_cert_cb>(SSL_CTX *ctx))(SSL *ssl, X509 **x509, EVP_PKEY **pkey);

=item void B<SSL_CTX_get_default_read_ahead>(SSL_CTX *ctx);

=item char *B<SSL_CTX_get_ex_data>(const SSL_CTX *s, int idx);

=item int B<SSL_CTX_get_ex_new_index>(long argl, char *argp, int (*new_func);(void), int (*dup_func)(void), void (*free_func)(void))

=item int B<SSL_CTX_get_quiet_shutdown>(const SSL_CTX *ctx);

=item void B<SSL_CTX_get_read_ahead>(SSL_CTX *ctx);

=item int B<SSL_CTX_get_session_cache_mode>(SSL_CTX *ctx);

=item long B<SSL_CTX_get_timeout>(const SSL_CTX *ctx);

=item void B<SSL_CTX_set_quiet_shutdown>(SSL_CTX *ctx, int mode);

=item void B<SSL_CTX_set_read_ahead>(SSL_CTX *ctx, int m);

=item void B<SSL_CTX_set_session_cache_mode>(SSL_CTX *ctx, int mode);

=item int B<SSL_CTX_set_ssl_version>(SSL_CTX *ctx, const SSL_METHOD *meth);

L<SSL_CTX_set_msg_callback(3)|SSL_CTX_set_msg_callback(3)>,

L<SSL_CTX_set_options(3)|SSL_CTX_set_options(3)>,

L<SSL_CTX_set_quiet_shutdown(3)|SSL_CTX_set_quiet_shutdown(3)>,

L<SSL_CTX_set_read_ahead(3)|SSL_CTX_set_read_ahead(3)>,

L<SSL_CTX_set_session_cache_mode(3)|SSL_CTX_set_session_cache_mode(3)>,

L<SSL_CTX_set_session_id_context(3)|SSL_CTX_set_session_id_context(3)>,

L<SSL_CTX_set_ssl_version(3)|SSL_CTX_set_ssl_version(3)>,